Download ELECTRONICS GLOSSARY

IPK06/05/17
ELECTRONICS GLOSSARY
-3G
Phones. Five times faster than 2.5G phones and 15 times faster than
2G phones.
-3GPP
3G Partnership Program.
-5.1 speakers
Location as recommended by the Audio Engineering Society.
L
C
R
o
30
o
100-120
LS
RS
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
A
-ac
Alternating current - a signal in which the current and voltage vary in
a repeated pattern over time.
-ACLR
Adjacent Channel Leakage Ratio
-ACPR
Adjacent Channel Power Ratio. A measure of spectral regrowth that
is the power leakage to adjacent channels of the designated channel.
-ADSL
Asymmetric Digital Subscriber Line
-ADSL2
Provides data transmission rates of 10 to 20 times that of conventional
DSL - 25Mb/s. It is backwards compatible with ADSL.
The downstream band operates at 1.1MHz for ADSL and 2.2MHz for ADSL2
-AdvancedTCA
-Aerials
Advanced Telecom Computing Architecture
Can consider as a the 'plug' that connects to the space where the wave
is. Basic requirement is that it should absorb as much power as possible and be resonant at the
frequency where it should operate.
A theoretically perfect aerial is used as a reference and radiates equally in all directions with 100%
efficiency. This aerial is acting an Isotropic radiator.
Aerial gain is simply the amount of power that is radiated in a particular direction compared to the
amount an isotropic aerial would radiate in that direction. It normally refers to the highest value.
Radiation patterns.
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side lobe
back lobe
main lobe
side lobe
half wave dipole
no coverage
quarter wave dipole
top view
no coverage
ground plane dependent
ground plane independent
Aerial gain is the ratio of an aerial's output signal strength to its input signal strength. It is usually
recorded in dBi - the larger the value the better.
-AES
Advanced Encryption Standard
-AiP
Antenna in Package
-air conditioning
Invented by Willis Carrier
-Air Interface
A wireless network's operating system, enabling communication
between a cell phone and its carrier. Examples include CDMA, TDMA, GSM, OFDM etc
-ALM
Adaptive Logic Module
-Amateur Radio Bands.
0.1357 - 0.1378MHz
1.810 – 2.0MHz
3.5 – 3.8MHz
7.0 – 7.1MHz
10.10 – 10.150MHz
14.0 – 14.35MHz
18.068 – 18.168MHz
21.0 – 21.450MHz
24.890 – 24.990MHz
28.00 – 29.7MHz
50.0 – 52.0MHz
70.0 – 70.5MHz
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144.0 – 146.0MHz
-AMBA
Advanced Microprocessor Bus Architecture
-AMI-C
Automotive Multimedia Interface Collaboration. Also known as the
IEEE 1394 bus. To be used in cars.
-AM LCDs
Active Matrix LCDs
-Amplitude Modulation
There are several variations of amplitude modulation (AM). The most common AM is the
commercial amplitude modulation used in AM radio broadcasting. Mathematically, this is
represented as
eq1
st   A1  mt cos2 f c t  ,
where s(t) is the modulated (or carrier) signal, m(t) is the modulating (message) signal, A is the
amplitude of the unmodulated carrier signal and fc is the carrier frequency. The modulation index is
defined as
eq2

  Amax Amin
2A
where Amax is the maximum value of A[1+m(t)] and Amin is the minimum value.
An AM waveform can be demodulated, ie m(t) can be recovered, by an envelope detector if   1.
When  > 1, the carrier signal is overmodulated, and the envelope is distorted.
If we assume mt   B cos2 f m t  with B > 0, equation 1 becomes
eq3
st   A cos2 f c t   0.5A cos2f c  f mt  0.5A cos2f c  f mt
where the modulation index,  = B. From equation 3, it is clear that the modulated signal, s(t),
contains the carrier frequency and two sidebands, fc + fm. Hence, the commercial AM is also called
double-sideband with transmitted carrier (DSB-TC) or double-sideband with large carrier
(DSB-LC). The ratio between the amplitudes of the carrier component and either sideband is 0.5.
For example, this ratio gives a 0.5 value or -6dB for a 100% modulation index, and a 0.25 value or 12dB for a 50% modulation index.
In general, the Fourier spectrum of s(t) can be shown to be
eq4
Sf   0.5Af  f c   f  f c   0.5AMf  f c   Mf  f c 
where M(f) is the Fourier transform of the modulating signal, m(t).
Double-Sideband Suppressed Carrier
Since the carrier component does not provide any information about the modulating signal, it is not
necessary to be transmitted. This leads to a double-sideband suppressed carrier (DSB-SC) AM,
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which has a better efficiency in power required for transmission, but needs a more complex
demodulation scheme. A DSB-SC waveform has the form as
eq5
st   Amt  cos2 f c t 
Similar to equation 3, a DSB-SC for a single tone modulation is represented as
eq6
st   0.5A cos2f c  f mt  0.5A cos2f c  f mt
If a four-quadrant multiplier is used to generate the product of A(1+m(t)) and the carrier waveform
cos(2fct) in equation 1, then the DSB-SC waveform can be easily generated with a 1V negative dc
offset, added to the desired message signal. If, however, a two-quadrant multiplier is used,
then s(t) = 0 for m(t) < -1.
-AMPS
Analogue Mobile Phone Service - used in the US. Represents the first
generation of wireless networks.
-AOI
Automated Optical Inspection
-APE
Associative Processing Elements
-APFC
Active Power Factor Correction. An automatic method of reducing
the harmonics generated on power supply lines by large motors. Often necessary to satisfy IEC
61000-3-2 current harmonic requirements.
-API
Applications Programming Interface.
-APR
Access Point Repeater.
-Armstrong
Edwin Howard Armstrong. Developed the superhet receiver in 1919
and the super regenerative receiver in 1921.
-ARPU
Average Revenue per User
-ASK
Amplitude Shift Keying. The carrier is amplitude modulated between
two levels. To save power, the lower level is usually near zero. The amplitude modulation of
digital pulses (signals)
-ASIC
Application Specific Integrated Circuit
-ASMR
Advanced Surface Movement Radar.
-ASP
Associative String Processor
-ASSP
Application Specific Standard Product.
-ATE
Automated Test Equipment
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-ATPG
Automatic Testy Pattern Generator
-ATSC
Advanced Television Standards Committee.
Broadcast formats defined by ATSC.
Definition
Lines/frame Pixels/line Aspect ratio
Frame rates
High (HD)
1080
1920
16:9
23.976p, 24p, 29.97p, 29.97i, 30p,
30i
High (HD)
720
1280
16:9
23.976p, 24p, 29.97p, 30p, 59.94p,
60p
Standard (SD) 480
704
4:3, 16:9
23.976p, 24p, 29.97p, 29.97i, 30p,
30i, 59.94p, 60p
Standard (SD) 480
640
16:9
23.976p, 24p, 29.97p, 29.97i, 30p,
30i, 59.94p, 60p
-Attenuation
For free space
2
 4 d 
Loss  10 log 

  
where d is the distance and  is the wavelength. For a 1GHz signal over a distance of 1000m the
loss is 92.4dB.
-Averaging
A processing technique used by digital oscilloscopes to reduce noise
in a displayed signal.
-AWGN
Additive White Gaussian Noise. Noise with a frequency spectrum
that is continuous and uniform over a specified band.
-AWS
Automatic Warning System
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
-Backdriving
Temporary overdriving the component outputs to force a node to its
opposite logic state
-backlash
The amount by which the width of a gear tooth space exceeds the
thickness of an engaging tooth, measured at the pitch circle of the gears. It allows for
manufacturing errors but also provides the necessary clearance for lubrication.
bandpass filter
A signal filter designed to pass a particular range of frequencies,
while attenuating frequencies outside that range.
-bandwidth
The range of frequencies that can be switched, conducted, or
amplified within certain limits.
-base band
The original band of frequencies produced by a transducer, such as a
microphone, prior to modulation.
-Baud
The number of signal level changes per second in a digital signal.
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-BCH
Bose-Chaudhuri-Hocquenghem. An error correction code, widely
used in WLAN applications and where multiple errors need to be detected and corrected
-BER
Bit Error Rate. A measurement of performance for digital
communication systems.
Bit Error Ratio. The number of erroneous bits divided by the total number of bits transmitted,
received, or processed over some period.
-BGA
Ball Grid Array
-Bias Tee
A component used for injecting a direct voltage or current into an RF
transmission line without disturbing the rf signal.
-BIT
Built In Test
-BITS
Building Integrated Timing Supply - Used with timing signals around
a network.
-Bit Rate
A measure of how fast binary digits can be sent through a channel.
Usually lower than the Baud rate
-Blocking
Blocking appears as a degradation in the output of a receiver when a
fairly close in frequency signal is increased in level.
-Bluetooth
Carrier frequency 2400MHz to 2483.5MHz. Divided into 79 channels, spaced at a maximum
interval of 1MHz.
Governed by a pseudo-random generator in the master, the signal sent to the slave hops from
channel to channel, dwelling on each channel frequency for a 675ns interval, which is called the
time slot.
The master transmits during even numbered time slots and the slave during odd numbered time
slots. Voice bits and data bits are transmitted in packets.
These packets may straddle one, three or five of the 675ns time slots.
Hopping - 1600 hops/s in normal operation (hop speed may vary depending upon the packet length.
Bluetooth has five hopping sequences:
1).
Page hopping sequence
2).
Page response sequence
3).
Inquiry sequence
4).
Inquiry response sequence
5).
Channel hopping sequence.
The first four are restricted hopping sequences used during connection setup. The normal channel
hopping sequence is pseudorandom, based on the master clock value and device address. The
periodicity of this hopping sequence is 23 hours and 18 minutes.
Modulation. Digital FM scheme. The peak frequency deviation allowed is 175kHz. 0.5 BT
Gaussian-filtered 2FSK at 1Msymbol/s - Modulation index:0.28 to 0.35 (0.32 nominal).
Modulation is two-level frequency shift keying (2FSK). The modulated carrier shifts between two
frequencies representing a "1" and a "0". Consequently, 2FSK provides one bit of data per symbol.
Bluetooth radios may operate as either master or slave units. A master can be actively
communicating with up to seven slaves, while another 200 or more slaves can be regestered in a
non-communicating, power-saving mode.
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Transmit power: Power class 1: 1mW to 100mW
Power class 2: 0.25mW to 2.5mW
Power class 3: 1mW
The asynchronous channel can support an asynchronous link of maximally 721Kbps in either
direction while permitting 57.6Kb/s in the return direction, or a 432.6Kbps symmetrical link.
Enhanced Data Rate (EDR) Addendum offers payload data rates of 2.1Mb/s. The selection of
2.1Mb/s was partly due to the modulation scheme and also to ensure backwards compatibility. The
EDR defines additional packet types that employ new modulation schemes for payload data.
Standard rate packets are made up of four sections, the access code used by the receiving device to
recognise incoming transmissions; a header describing the packet type and length, the payload itself;
and the inter-packet guard band.
All of the transmit sections use Gaussian frequency shift keying (GFSK) to modulate the over air rf
signal. The carrier frequency deviates by + 160kHz to indicate a zero or a one, thus encoding one
bit per symbol. The sample rate is at 1MHz. The overhead required for the access code header and
guard band mean that the maximum payload data rate is 721kb/s.
EDR packets use GFSK modulation for the access code and header, but use one of two different
modulation schemes for the payload as well as requiring the insertion of a small guard band and
synchronisation sequence between the header and the payload. The DDR (double data rate)is
mandatory, uses /4 differential quadrature phase shift keying or /4-DQPSK and can double the data
rate whilst tolerating a lot of noise. This varies the phase and not the frequency of the carrier.
Quadrature refers to the fact that there are four possible phase positions for each symbol, allowing
two bits of data to be encoded per symbol. The symbol rate remains the same, hence the DDR. The
scheme is differential because it is the phase position of each symbol relative to the previous
position (the differential move) that determines the value which is encoded. The /4 designator
means that the differential move is +3 /4, + /4, - /4 or -3 /4. This avoids phase jumps of + p,
guarding against large amplitude variations and enabling demodulation without knowledge of
carrier phase. A raised cosine pulse shaping filter is used to reduce side band emission.
The triple data rate is optional and uses 8- DPSK (8- phase differential phase shift keying). The
smaller phase difference between adjacent positions means that it is more vulnerable to interference,
but it allows the encoding of three bits of data per symbol.
There are 10 new EDR packets in total, five each for the double and triple data rates. Two of the
five are three slot and five slot eSCO (extended synchronous connection orientated) packets, which
use reserved bandwidth and are typically used for voice communication. The remaining three are
one, three and five slot ACL (asynchronous connectionless) packets, which are used for data
transfer.
None of the new packets employs FEC (forward error correction). Instead the existing CQDDR
(channel quality driven data rate) algorithm is extended to automatically switch back to standard
rate packets with FEC when necessary. There are also changes to the method of handling of the
packet header's packet type field to accommodate the new packet types.
-Bode Plot
Developed by Hendrick Bode at Bells Labs in the 1940s. It is a graph
that shows how the gain and phase of a system vary with frequency when the system is driven by a
sinusoidal input.
-BPON
-BPSK
Broadband Passive Optical Network
Binary Phase Shift Keying. This is a digital modulation technique.
The phase of a constant amplitude carrier is switched between two values based on whether the base
band signal is a 0 or a 1. This modulation technique can be used for sending data over a coaxial
cable network.
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-BS7671
Building Electrical Regulations. Part P, Electrical Safety, introduced
on 1st January 2005. It is now a requirement that new, repositioned or repaired socket outlets are
not put into service until tested. These tests include, continuity testing of protective conductors and
ring main final circuit conductors, measurement of insulation resistance, checking of polarity and
measurement of earth fault loop impedance
-Buck Switching Regulator.
Reduces a direct input voltage Vi with a switch (S) and a series inductor (L) to a stabilised low
direct output voltage Vo. The stabilisation is achieved by changing the on-state time of the switch.
When the switch is closed, the inductor stores a part of the output current as magnetic energy.
When the switch opens, the magnetic energy is released together with the charge from the capacitor
C and maintains the output voltage, Vo. The output voltage is directly dependent on the duty factor
(ton/toff).
Both the switch and the freewheeling diode can be usefully replaced with MOSFET switches. Have
a much faster response time and much smaller on resistance. Need to be controlled directly from
the pulse width modulator circuit.
energy storage
energy storage inductor
L
S
Vo
Vi
freewheeling
diode
charge
C
R
smoothing
S
energy release
energy storage inductor
L
Vo
Vi
discharge
C
freewheeling
diode
R
smoothing
With careful designs, such circuits can achieve >95% efficiencies.
-Buzzers
Miniature audio buzzers - having a vibrating diaphragm. They are
electromagnetic and contain the circuit below to maintain oscillation.
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+Vs
L1
L2
0V
L1 is the driving coil and L2 provides feedback. When current flows through L1 and the diaphragm
begins to vibrate, coil L2 detects its vibration, providing feedback to the base of the transistor so
that the oscillation becomes synchronised with the vibration of the diaphragm.
These buzzers need to be secured firmly to a solid surface in order to ensure that there is adequate
mechanical vibration and hence feedback in order to maintain strong oscillations.
-BVDSS
Break down Voltage Drain to Source
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
-CAF
Conductive Anodic Filamentation - a condition that can emerge in
PCBs. An electrochemical process that occurs within glass reinforced epoxy resin substrates such
as FR4 and effectively causes the board to break down.
-CAGR
Compound Annual Growth Rate
-CAM
Content Addressable Memory
-CAN
Controller Area Network - The current In -vehicle networking
standards. Medium speed (ISO11519 - Class B: 10 to 125kb/s) High speed (ISO11898 - Class C:
125kb/s to 1Mb/s)
-Capacitor Colour Code.
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470000pF = 470nF, 10%, 400V
Black
Brown
Red
Orange
Yellow
Green
Blue
Violet
Grey
White
0
1
2
3
4
5
6
7
8
9
Black
Brown
Red
Orange
Yellow
Green
Blue
Violet
Grey
White
0
1
2
3
4
5
6
7
8
9
Red
250Vdc
Yellow 400Vdc
White
Black
+/-10%
+/-20%
Orange x 1000
Yellow x 10000
Green x 100000
Multiplier in pF
Sub miniature ceramic plate capacitors. The tip colour indicates temperature coefficient.
Red/Violet
P100
Red
N075
Violet
N750
Orange
N150
Yellow
N220
Green
N330
Black
NP0
No colour
2F5
The numbers after the N or P refer to the change in ppm/Kelvin
There is a tolerance on the temperature coefficients and NP0 ones can be +/-30ppm
-CAT rating
Describes the electrical environment that the equipment is designed
for, including the transient voltage withstand rating.
CAT I
For measurements performed on circuits not directly connected to mains. When
measuring 300V rms signals, you can expect to see transients up to 1.5kVpk
CAT II
For measurements performed on circuits directly connected to the low voltage
installation. When measuring 300V rms signals, you can expect to see transients up
to 2.5kVpk.
CAT III
For measurements performed in the building installation. When measuring 300V
rms
signals, you can expect to see transients up to 4kVpk.
CAT IV
For measurements performed at the source of a low voltage installation (<1000V).
When measuring 300V rms signals, you can expect to see transients up to 6kVpk.
-CBR
Constant Bit Rate.
-CCD
Charge Coupled Device.
-CCFL
Cold Cathode Fluorescent Lamp
-CCP
Customer Convenience Port
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-CCT
Cold Cathode Tube
-CDMA
Code Division Multiple Access
-CDPD
Cellular Digital Packet Data. Early system used on AMPS
-CDR
Clock and Data Recovery
-CEMs
Contract Electronic Manufacturing services.
-Cermet
A composite material made from ceramic and metallic materials. The
metal is used as a binder for an oxide, boride, carbide, or alumina. Generally the metallic elements
used are nickel, molybdenum and cobalt. It is used in the manufacture of resistors, especially
potentiometers, capacitors and other components which may experience high temperatures.
-CFD
Computational Fluid Dynamics.
-CIC
Cascaded Integrate and Comb filter.
-CIM
Computer Integrated Manufacturing
-Circuit Switching
Used in phone systems - a dedicated connection. That channel cannot
be used by any other user. See Packet Switching.
-Class D
Triangular wave generator at 200kHz
-CLDC
Connected Limited Device Configuration
-CML
Current Mode Logic
-CMOS
Complementary Metal-Oxide Semiconductor. The CMOS fabrication
process constructs logic elements from complementary pairs of p-channel and n-channel MOSFETs,
wired back to back so that current flows only momentarily while the element is actually switching
and none flows in its fully on or fully off states. This enormously reduces power consumption
compared with older bipolar transistors, which conducted while on.
-CMOS Image sensors
Digital Cameras etc. Higher noise than CCDs but much easier to
make. Typical sensor cell shown below.
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green current
red current
blue current
n lightly doped drain
0.2 m
blue photon collection
p-well
n-well
0.6m
green photon collection
2m
red photon collection
p-substrate
-CMP
Chemical mechanical planarization: The use of a compound to polish
a wafer's surface to eliminate topological layer effects in the manufacturing of semiconductors and
MEMS.
-CNT
Carbon NanoTubes
-COB
Chip on Board
-COFDM
Coded Orthogonal Frequency Division Multiplexing. Used for DVBT transmissions. The terrestrial network operator can choose any combination of number of
carriers, guard interval, constellation and convolutional code rates. COFDM involves modulating
data onto a large number of carriers using the FDM techniques. For example, one DVB-T standard
modulates the signal onto 8k sub-carriers within an 8MHz band. Coded OFDM means that the data
transmitted on the sub-carriers is protected by FEC (Forward Error Correction) coding. The
property of orthogonality for communication signals means that signals that are orthogonal to each
other can be transmitted together and not interfere with each other. Therefore placing the subcarriers orthogonal to one another makes it possible to transmit them in parallel without
interference. The individual spectra of each of the sub-carriers can overlap and still not interfere
with one another.
-COM
Computer on Module. It just incorporates the processor and standard
interfaces such as PCI Express and serial ATA
-common mode
Common mode signals are identical signals that are applied to both
inputs of a differential amplifier. An ideal differential amplifier rejects all of the common mode
signals.
-Communication satellites.
Artificial satellites that functions as part of a global radio-communications network. Echo 1, the
first communications satellite, launched in 1960, was an instrumented inflatable sphere that
passively reflected radio signals back to earth. Later satellites carried with them electronic devices
for receiving, amplifying, and rebroadcasting signals to earth. Relay 1, launched in 1962 by the
National Aeronautics and Space Administration (NASA), was the basis for Telstar 1, a
commercially sponsored experimental satellite. Geosynchronous orbits (in which the satellite
remains over a single spot on the earth's surface) were first used by NASA's Syncom series and
Early Bird (later renamed Intelsat 1), the world's first commercial communications satellite.
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In 1962, the U.S. Congress passed the Communications Satellite Act, which created the
Communications Satellite Corporation (Comsat). Agencies from 17 other countries joined Comsat
in 1964 in forming the International Telecommunications Satellite Consortium (Intelsat) for the
purpose of establishing a global commercial communications network. Renamed the International
Telecommunications Satellite Organization in 1974, Intelsat now has 143 member agencies, a
network of 17 satellites in geosynchronous orbits that provides instantaneous communications
throughout the world, and more than 2,000 earth stations to transmit and receive signals to and from
the satellites. It has orbited eight series of Intelsat satellites, beginning with Intelsat 1 (Early Bird) in
1965. The satellites in the current series, Intelsat 8, can carry 22,500 two-way telephone calls and
three color television broadcasts at the same time; this could be increased to as many as 112,500
two-way telephone circuits using advanced electronic equipment.
Comsat is also the U.S. representative to the International Mobile Satellite Organization (Inmarsat).
Established in 1979 to serve the maritime industry by developing satellite communications for ship
management and distress and safety applications, Inmarsat was originally called the International
Maritime Satellite Organization but changed its name to reflect its expansion into land, mobile, and
aeronautical communications. Its users now include thousands of people who live or work in
remote areas without reliable terrestrial networks. Inmarsat presently represents 86 member
countries and has nine satellites in geosynchronous orbits—four of these satellites, the latest
Inmarsat-3 generation, provide overlapping global coverage, and the remainder are available as
spares or for leasing to other organizations.
In addition to the Intelsat and Inmarsat satellites, many others are in orbit. These are used by
individual countries, organizations, and commercial ventures for internal communications or for
business or military use. A new generation of satellites, called direct-broadcast satellites,
communicates directly with small domestic antennas to provide such services as cable like
television programming.
-conduction loss
In a power semiconductor, the conduction loss is the energy dissipated
by the device while current is lowing, usually defined as the time period between the turn-on event
and the turn-off event.
-Contactless Smart Card
The reader emits an em field at 13.56MHz. The Smart Card antenna picks up enough energy to
power the card. The reader communicates to the card by modulating its emitted field using 10%
amplitude shift keying. The smart catrd responds by modulating its power consumption usimg a
sub-carrier frequency of 847kHz
-COT
Customer Own Tooling
-COTS
Commercial Of The Shelf
-CPE
Customer Premises Equipment
-CPCI
Compact PCI
-CQDDR
Channel Quality Data Driven Rate. Used with Bluetooth devices to
gauge how much of the data is being corrupted and then to adjust the size of the data packet to suit.
-Cross Modulation
A related phenomenon to IMD and in its simplest form is the transfer
of the modulation of one signal onto the carrier of another. Like IMD it is caused by non-linearity
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in the active devices when a large signal drives the active device into the non-linear region of its
operating parameters. In general IMD products will be heard before cross modulation.
-CRT
Cathode Ray Tube - the television version invented by Philo Taylor
Farnsworth.
-Crystals
See Quartz crystals
-CSP
Chip Scale Package
-CTO
Chief Technical Officer
-CVD
Chemical Vapour Deposition is a means of laying down material on
the top of a wafer.
-CWDM
Coarse Wave Division Multiplex
DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
-DAB
Digital Audio Broadcasting. Broadcasts in the 217 - 230MHz band.
See Digital Radio
-DAP/DNA
Digital Application processor/Distributed Network Architecture
-DAQ
Data AcQuisition
-DARPA
Defence Advanced Research projects Agency
-DBR
Distributed Bragg reflector. A laser in which the etched grating is
physically separated from the electronic pumping area of the semiconductor laser.
-dc
Direct current - a signal with a constant voltage or current
-DCF
Dispersion Compensation Fibre - the traditional method of
compensating for chromatic dispersion in optical fibres in the days before DWDM.
-DCG
Dispersion Compensation Gratings - used to correct for chromatic
dispersion in optical fibres
-DC motor
The simplified expression for the total torque, T, developed in a dc
motor is given by
T = KTI
where KT is a constant for the motor, I is the armature current and  is the flux produced by the
field.
Permanent magnet motors.
An advantage of this type of motor is that no electrical supply is needed to produce the magnetic
field so its overall size is smaller than dc motors with field coils. Many permanent magnet materials
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have a working temperature less than the normal operating condition of many motors so torque is
normally limited to 150% of its rated value to prevent demagnetisation.
The flux in a permanent magnet dc motor is constant and therefore, from the first equation, the
torque developed is directly proportional to the armature current. Additionally, as shown in the
second equation, the speed is proportional to the supply voltage.
As the armature rotates in the magnetic field, an emf is induced in the armature circuit. This emf
always acts against the source voltage and is therefore known as the back emf. The value of this
back emf, E, is dependent upon the flux produced by the field and the armature speed, and is
expressed as
E = kN
where k is the constant for the motor,  is the flux and N is the speed of rotation.
The equivalent circuit for the armature of a dc motor is shown below.
I
R
V
E
M
The supply voltage must always be larger than the back emf or no armature current would flow and
the armature would not rotate. So
V = E + IR
where V is the supply voltage, E is the back emf, I is the current and R is the armature resistance.
By replacing E and rearranging the equation for the speed becomes
N = (V - IR)/k
where k is the constant for the motor,  is the flux, V is the supply voltage, I is the armature current
and R is the armature resistance. Since the flux in a permanent magnet dc motor is constant, the
speed is proportional to the supply voltage.
In theory the speed of the dc motor would keep increasing with increasing supply voltage. In
practice this is not so and mechanical and elecrical restrictions (particularly in the commutation)
result in a maximum speed being imposed for each motor. Initially the motor will produce a
constant torque regardless of speed, but beyond a certain speed the torque reduces very quickly and
rapidly drops to a low level.
Wound field motors.
In a wound field dc motor the magnetic flux produced by the field windings is variable and can be
used to control both the torque and the speed.
The torque speed characteristic of a dc motor is shown in the graph below.
torque
constant
torque
area
field
weakening
area
base
speed
speed
IPK06/05/17
If the field and armature windings are supplied with their full voltage, the motor will run at its base
speed. If the armature voltage is reduced while maintaining the field voltage, the motor will run at a
speed less than the base speed, but will maintain a constant torque. To run the motor beyond base
speed, the field voltage is reduced while the armature voltage is maintained, resulting in the speed
increasing but the torque being reduced.
The classification of wound field dc motors depends on the different interconnections of the field
and armature circuits, which can take the form of parallel (shunt), series or compound. In these
configurations the reversal of the supply voltage does not reverse the motor. Reversal of the motor
is now only possible by reversing either the armature or the field connections.
Shunt motor.
In a dc shunt motor the field and armature circuits are connected in parallel to the supply. They are
suitable for constant speed control applications as their speed drops only slightly with increasing
load. On start up, very large currents can flow and a starting resistance is essential to limit these
currents. As the motor speed increases, the starting resistance can be gradually removed.
Series motor.
The armature and field windings are connected in series across the dc supply. They are suitable for
traction applications as at low speeds they have a high torque that gradually decreases as the speed
increases. This type of motor should always have a load permanently connected since under no load
conditions very high speeds can be produced.
Compound motor.
This is a combination of the other two types. Often formed for specialist applications and for heavy
duty applications where a high starting torque is essential.
Separately excited motor.
This is similar to the shunt motor except that there is a different voltage source for the field and
armature circuits. Can be more efficient that the conventional shunt motor.
One of the problems associated with the construction of dc motors is armature reaction. This occurs
because the current flowing through the armature winding produces a magnetic field which affects
the flux pattern and causes distortion to the magnetic field. This produces a shift in the neutral
plane that will affect the commutation. If the brushes were to remain in the old neutral plane, they
will short circuit coils that have voltage induced in them, causing arcing between the brushes and
commutator.
Toprevent such arcing, the brushes must be rotated to the new neutral plane. However the effect of
the armature reaction varies with the load current, and so every time the load current varies, the
neutral plane shifts and the brush position must be changed. To help eliminate the effects of
armature reaction, interpoles and compensation windings are used. The compensation windings
consist of a series of coils embedded in slots in the pole faces. These coils are connected in series
with the armature and will produce a magnetic field, the strength of which varies directly with the
armature current. They are wound so as to produce a field that opposes the magnetic field of the
armature, tending to cancel the effects of the armature's magnetic field. The motor is then said to be
compensated.
Interpoles are small auxillary poles located on the yoke between the main field poles of the motor.
They have the effect of reducing the armature reaction effect in the commutating zone, and consis of
a few turns of thick wire connected in series with the armature. Interpoles are wound and placed so
that each has the same magnetic polarity as the main pole ahead of it, in the direction of rotation.
The field generated by the compensating windings tends to cancel the armature reaction.
-DCS
Distributed Control System.
-DCS
Digital Cellular System. DCS-1800. Phones use frequencies in the
1800MHz band.
IPK06/05/17
-DCT
Direct Cosine Transform
-DDR
Double Data Rate - memory. First introduced in 2000 mostly in
graphics cards. Needs three highly regulated voltages, VDDQ, VTT and VREF. VDDQ is the main
high current supply typically 2.5V. VTT is a memory bus termination voltage that is half VDDQ.
VREF is a low power reference voltage that tracks at half of VDDQ and to which VTT is compared,
where VTT = VREF.
-Defibrillator
Monophasic waveform. A capacitor and inductor are switched to the
patient's chest via a high voltage relay to deliver a big pulse, usually between 200 and 360J of
energy. Voltages involved 4-5kV. Biphasic systems do not require so much energy and can use
lower voltages. Such systems produce both a positive and negative pulse. Monophasic systems just
produce a positive pulse.
-DES
Data Encryption Standard
-DFB
Distributed feedback. A resonant cavity laser using grids etched into
the bottom of a semiconductor substrate as a reflective medium.
-DFT
Design For Test
-DFM
Design for Manufacture
-DFV
Design For Verification
-DFY
Design For Yield
-Differential signals
Signals that are referenced to each other, rather than ground.
-Digital Radio
Broadcast at 256Kbps.
Radio Data System (RDS) developed in the late 1970s.
DAB developed by the Eureka 147 consortium in 1987. It promises better reception than analogue
broadcasts as the transmission is helped, rather than hindered by high rise buildings and mountains.
Can operate at any frequency between 30MHz and 3GHz. The overall bandwidth of a DAB
transmission is just over 1.5MHz and this gives a bit rate of 1.5Mbps. Several services are
contained within a DAB channel including data about the broadcast so that the radio can display the
station, program information and so on.
This group of services packaged into one signal is known as a multiplex. It will also carry data that
tells the digital radio's decoder how the multiplex is configured so that the radio can interpret it
correctly. The services that make up the multiplex are created by the broadcaster and then
individually coded and error protected. They are then put into a predetermined configuration in the
MSC (Main Service Channel. Here it is joined by information about the nature of the service and
the configuration of the multiplex.
OFDM splits the signal into several narrow band channels at different frequencies. The signal is
then transposed to the required radio frequency band, amplified and then transmitted.
IPK06/05/17
OFDM
DAB signal
transmitter
FIC
service information
multiplex information
transmission
multiplexer
audio
services
audio
encoder
channel
coder
data
services
packet
mux
channel
coder
radio
frequency
MSC
mux
At the receiver the multiplex is separated back inti its individual services. First it goes through the
OFDM demodulator. The service information and multiplex configuration data is sent via the FIC
(Fast Information Channel) to the user interface. You can then choose a particular broadcast and the
radio receives the appropriate signal. The other audio and data services are sent through the OFDM
demodulator to the channel decoder where any transmission errors can be corrected. The audio part
of the DAB is sent via an audio decoder to the speakers, while all other services are sent to a
separate data decoder.
partial
MSC
tuner
OFDM
demodulator
FIC
control bus
channel
decoder
audio
decoder
audio
services
packet
demux
data
services
controller
user interface
Because digital radio signals use the natural and manmade landscape as reflectors, multiple paths
exist between the transmitter and the receiver. This means the transmission of DAB signals has to
be spread out in time and frequency, so any channel distortions can be eliminated in the receiver.
But the signal received is many times stronger than an analogue radio broadcast resulting in better
sound quality.
In there UK there are 7 Multiplexes available in the range 217.5 to 230 MHz - called Band III in the
UK. Each multiplex can carry up to 1.28Mb/s of content - split up between the services. Mono talk
radio can be delivered at 64kb/s whereas stereo music is generally delivered using 192 to 224kb/s.
20% can be used for data transmissions.
In some countries Band III is still used for analogue television. In these countries, L Band, 1228 to
1575MHz is used for DAB. In 2007 L Band frequencies will become available in the UK.
IPK06/05/17
DAB uses up to 1536 carrier frequencies distributed over a 1.5MHz wide band rather than just one
carrier (as in VHF FM). So interference only affects some of the carriers and the majority are
always received noise free (OFDM).
Mobile reception is affected by:Doppler effects - which causes slight frequency shifts leading to time dependent interference.
Multipath reception - the receiving aerial receives signals directly as well as portions of signals
reflected from buildings and hills. The overlap with each other causes frequency dependent
interference.
Multipath reception - the direct and reflected signals reach the receiver at different times. The bits
for transmission are transmitted in groups, known as symbols. Multipath reception can cause the
symbols adjacent in time to overlap each other, due to them arriving at different times. To prevent
this, the symbol duration is lengthened by a guard interval at the transmitter. This provides the
receiver with a clean symbol since it delays using the symbol until any overlap has ended.
Significant error checking and correction bits are also transmitted, making it possible to reconstruct
the transmitted bit sequence in the receiver. FEC - Forward Error Correction.
-DLL
Delay Lock Loop
-DLP
Digital Light Processing. Digital cinema. TI product and technology.
-DMB
Digital Multimedia Broadcast
-D-MEMs
Diffractive MEMs
-DNL
Differential Non-Linearity (DACs)
-DPA
Distributed Power Architecture.
-DPMO
Defects Per Million Operations.
-DPO
Digital Phosphor oscilloscope. Work by emulating the intensity
grading of an analogue scope. The digital waveform signal is mapped to a database of cells that
represents the screen positions. The database is fed into the display and the waveform is seen as
with an analogue scope, but the DPO allows different intensities to be displayed in different colours.
-DRAM
Dynamic Random Access Memory.
-DRO
Dielectric Resonator Oscillator
-DSC
Digital Signal Controller
-DSD
Direct Stream Digital. DSD samples at 2.8224MHz, storing the
sound as single bit data.
-DSL
Digital Subscriber Line
-DSM
Deep-SubMicron. Fabrication method for ICs.
IPK06/05/17
-DSO
Digital Signal Oscilloscope. In DSOs, the ADC samples the signal at
many points and converts the voltage at these points to digital information - the user sets the
sampling rate. These sample points are stored in memory as waveform points that are used to create
the waveform image. The trigger determines the start and stop points of the waveform record.
-DSS
Dynamic Self Supply
-DSSS
Direct Sequence Spread Spectrum. Used in IEEE802.11.
Also see FHSS. Used to avoid interference due to narrow-band carriers. Each data bit is coded
using a fast pseudo-random sequence. In this way the data signal can be spread spectrally and each
individual bit is transmitted as a type of noise over the entire 84MHz wide band. In the receiver the
transmitter's pseudo-random sequence is recognised and the signal regenerated and at the same time
the interference signalon the wireless link is spread, ie spectrally widened and its level significantly
reduced. In this way narrow-band sources of interference have no effect with this technique.
-DSP
Digital Signal Processor
-DSN
Deep Space Network
-DTM
Device Type Manager
-DTMF
Dual Tone Multiple Frequency. Also known as Touch tone or simply
tone dialling with telephones. Two bands of frequencies are used. A low band (697 to 941Hz) and
a high band (1209 to 1633Hz). The frequencies are chosen so that they are not harmonically related.
A valid DTMF signal consists of one frequency from the lower band and one from the higher band.
This gives 16 unique combinations representing the numerals from zero to nine plus * # A B C D.
A B C D are not available to the telephone user but can be used for testing.
DTMF Input
Data Output
F low
F high
Number
D3
D2
D1
D0
697
1209
1
0
0
0
1
697
1336
2
0
0
1
0
697
1477
3
0
0
1
1
770
1209
4
0
1
0
0
770
1336
5
0
1
0
1
770
1477
6
0
1
1
0
852
1209
7
0
1
1
1
852
1336
8
1
0
0
0
852
1477
9
1
0
0
1
941
1336
0
1
0
1
0
941
1209
*
1
0
1
1
941
1477
#
1
1
0
0
697
1633
A
1
1
0
1
770
1633
B
1
1
1
0
852
1633
C
1
1
1
1
941
1633
D
0
0
0
0
-DTT
Digital Terrestrial Television
IPK06/05/17
-DUT
Device Under Test
-DVB
Digital Video Broadcasting.
-DVB-C
Digital Video Broadcasting - Cable
-DVB-S
Digital Video Broadcasting – Satellite.
Digital Video Broadcasting – Terrestrial. Uses COFDM. DVB-T
uses 1705 of a total of 2048 carriers in the 2k mode and 6817 of 8192 carriers in the 8k mode. 1512
(2k) or 6048(8k) carriers are assigned information data, the remaining carrierstransmit reference
signals or sync patterns. The flexibility to choose the number of carriers, guard interval,
constellation and convolution code rate provides extensive trade-off between ruggedness and
capacity. For example, in an 8MHz TV channel, useful data rates from approximately 4.98 to
32Mb/s can be transmitted.
The rf DVB-T signal received at the aerial is initially down converteddirectly to the first IF of
36.167MHz. The ADC resolution is usually 8 or 10 bit and sampling frequency is 20.48Msamples/s
for DVB-T. The process of under sampling mixes the 36.17MHz input to the ADC to 4.79MHz at
its output, resulting in a spectrally inverted OFDM signal centres at 4.79MHz. This signal is then
converted to a complex signal in baseband. Then various digital processing is performed to obtain
the MPEG video and audio data. The maximum carrier frequency for DVB-T is 862MHz.
-DVB-T
-DVI
Digital Visual Interface. Used to connect a video source device, such
as a DVD player to a high definition display. Backed by the movie and TV industry.
-DVR
Digital Video Recorder
-DWDM
Dense Wave Division Multiplexing. A method of passively
combining multple wavelengths by colour.
-DXCO
-Dynamic range
Digitally Controlled Crystal Oscillator
The Dynamic range of a receiver is the range of input signals over
which the IMD products can be ignored, ie they are below the noise of the receiver. A useful
practical definition of dynamic range is two thirds of the difference in dB between noise floor and
the third order intercept point.
IPK06/05/17
Intercept point
Output Power
Extrapolated output
Extrapolated IMD power
1dB compression
point
Fundamental
Output
3rd Order
Intermodulation
Product
Input Power
EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE
-EAM
Electro-Absorption Modulator. Acts as a transceiver that converts
radio signals into light and vice versa. Can modulate frequencies from zero to 40GHz. Chipo level
modulation devices often integrated into hybrid transponder devices alongside lasers
-Earthing
The purpose of earthing is to minimise the risk of electric shock
should anyone touch metal parts when there is a fault present. This is achieved by providing a path
for fault current to flow safely to earth, which also causes the protective device (fuse etc) to
disconnect the circuit, removing the danger.
The purpose of earth bonding is to minimise the risk of electric shock to anyone who may be
touching two separate conductive parts when a fault occurs somewhere in the supply or in the
electrical installation. This is achieved by connecting bonding conductors between particular points
to minimise the voltage that may be created between them under fault conditions.
There are two types of bonding recognised by BS7671 - main and supplementary. Main
equipotential bonding is part of the protective measure of Earthed Equipotential Bonding and
Automatic Disconnection of Supply (EEBAD). Supplementary equipotential bonding is an
additional protective measure to EEBAD required in certain special installations or locations of
increased shock risk such as those in Part 6 of BS7671 which include locations containing a bath or
shower and swimming pools. Supplementary bonding conductors directly connect together all
exposed-conductive-parts and extraneous-conductive parts and are NOT intended to be directly
connected to the MET (Main Earthing Terminal). www.niceic.org.uk
-ECC
Elliptic Curve Cryptography
-ECC
Error Correction Code
-ECDL
External Cavity Diode Laser, using a cavity that is separated from the
lasing device. Usually employs some form of MEMS to actuate the reflective area for the laser.
-ECM
Electret Condenser Microphone.
IPK06/05/17
A condenser microphone consists of a very light diaphragm and back plate to which is applied a
polarizing voltage. The principle of operation is that sound waves impinging on the diaphragm
cause the capacitance between it and the back plate to change in sympathy. This in turn induces an
ac voltage on the back plate.
Because the capacitance is small, the electrical impedance is high and so a FET is incorporated into
the microphone to transform the impedance to a lower level suitable for feeding an amplifier via a
screened lead.
The ECM operates in a similar manner to a condenser microphone except that it has a permanent
charge voltage implanted in an electret material to provide the polarizing voltage. This can be
achieved in three ways, the most common being when the diaphragm is the electret material with
one side being metallised. This is known as the foil or diaphragm type. The electret material does
not make the best diaphragm and where higher performance is required, the diaphragm is made of
other material and the electret material is applied to the back plate. This is known as the back type.
A recent variation of this is when the electret material is at the front and this is known as the front
type. Here the electret material is applied to the inside of the front cover of the microphone and the
metallised diaphragm is connected to the input of the FET. This works by variation in capacitance
between the front cover and the diaphragm caused by sound waves impinging on the diaphragm.
A major advantage of the ECM is its immunity to vibration, resulting from the very low mass of the
diaphragm. This is particularly useful in the field of telecommunication and where it is installed in
equipment incorporating moving parts such as motors in dictation and cassette recorders.
The sensitivity is defined as output voltage for specified acoustic stimulus and load conditions and
is expressed in dBV/bar
ECMs have a wider frequency range than dynamic microphones.
Signal to noise ratio is defined as the inherent noise generated by the microphone without acoustic
stimulus relative to a sound pressure level at 1bar.
An electret microphone does not need a polarizing voltage or current. However it does require a
small feed current of between 50A and 1mA to power the FET.
FET impedance converter
R
1 - 2.2k 
+Vs 1.5 - 10V
ECM unit
output
C
0V
Shield case
-ECU
Electronic Control Unit
-EDA
Electronic Design Automation.
-EDAC
Error Detection and Correction
-EDC/ECC
Error detection/Error correction algorithm
-EDD
Electronic Device Description. Generated by means of the Electronic
Device Description Language
IPK06/05/17
-EDGE
Enhanced Data GSM Environment. Delivering data rates up to
384kbps. Essential to the 2.5G phones enabling voice, data, Internet and other connectivity
services. Normal GSM gives 14.4kbps.
Channel bandwidth - 200kHz
Raw channel bit rate - 812.5kbps
User bit rate - up to 384kbps
Modulation - 8PSK
-EDK
Evaluation and Development Kit
-EDT
Embedded Deterministic Test
-EEBAD
Earthed Equipotential Bonding and Automatic Disconnection of
Supply
-EECA
European Electronics Components Manufacturers Association
-Elliptical filters
L2
L1
C2
50
C1
C4
C3
50
C5
For 20m:
L1 is 14T 18swg on T50-10, L2 is 13T 18swg on T50-10, C1 = 200pF, C2 = 22pF, C3 = 330pF,
C4 = 56pF, C5 = 180pF
For 80m:
L1 is 21T 18swg on T68-2, L2 is 20T 18swg on T68-2, C1 = 820pF, C2 = 82pF, C3 = 1360pF,
C4 = 220pF, C5 = 680pF
-EMC
Electromagnetic Compatibility. Came into force on 1st January 1992
and the UK adopted it on 28th December 1992. From the 1st January 1996, all products sold - not
just new ones - must be marked with the "CE mark" to show conformance.
-EMI
Electromagnetic Interference. A unwanted electrical signal that is
either generated by a circuit or coupled into a circuit which affects or corrupts the quality of the
desired signal.
-EMR
ElectroMagnetic Radiation
-EMV
Latest smart card standard
-ENR
Energy per bit over the total Interference and noise power density of
the dedicated traffic channel.
IPK06/05/17
-EPCIA
European Passive Components Industry Association
-EPV
Embedded Process Verification
-ESAN
Embedded System Area Network
-ESD
Electrostatic Discharge
-ESP
Embedded Standard Products
-ESR
Equivalent Series resistance
-ESS
Environmental Stress Screening
-EtherCat
Ethernet for Control and Automation Technology
-ETSI
European Telecommunications Standard Institute
-Eureka 147
a standard that defines the delivery of terrestrial broadcast service of
data
-EUT
Equipment Under Test
-EVM
Error Vector Magnitude
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
-fab
Fabrication plant
-Fabrey-Perot
The simplest form of fixed-frequency semiconductor laser, based on a
resonant cavity design using the wafer substrate material as the end mirrors.
-FBAR
Film Bulk Acoustic Resonator. Developed by Dr Richard Ruby at
Agilent labs. He sandwiched an aluminium nitride film between two metal layers that serve as
terminals to create resonators. Similar to SAWs but able to operate at higher frequencies.
-FBG
Fibre Bragg Gratings. Act as very accurate optical filters. These in
fibre components have a pattern of lines 'written' by UV light onto the core of the fibre itself. These
cause periodic variations in the refractive index of the core which, depending upon the pattern,
allow specific wavelengths to be reflected. Can be used to compensate for chromatic dispersion and
then known as Dispersion Compensation Gratings or DCGs.
-FCRAM
-FEC
Fast Cycle RAM
Forward Error Correction. A mathematical method of encoding data
so that errors can be detected and corrected on receipt. Used with fibre cables - improves optical
signal to noise ratio. Based on original work of C.E. Shannon. Also used with DAB
IPK06/05/17
-FED
Field Emission Display. A low cost, low power, high performance
alternative to LCDs. They are effectively tiny, flat cathode ray tubes. They work by having a two
dimensional electron source and a phosphor material to emit the light, which creates the image.
They provide a viewing angle of 180.
-Ferrite materials
A polycrystal, sintered material with high electrical resistivity. The
high resistance of ferrite makes eddy current losses extremely low at high frequencies. Therefore,
unlike other magnetic components, ferrites can be used at high frequencies, with Manganese-zinc
ferrites used at frequencies up to several megahertz.
The extremely high purity basic ferrite materials are mixed, calcined, milled, granulated, formed by
pressing and sintered at a temperature of 1000C to 1400C, then machined. The electrical and
mechanical properties of a particular ferrite material are obtained by the material formulation and
the processing applied.
Typical technical data (at room temp.):
Dielectric constant
240-300 (Mn-Zn ferrite) 10-13 (Ni-Zn ferrite)
Specific heat
800J/kgC
Thermal conductivity
1-5W/mC
Coef. linear expansion
7-10 x 10-6/C
The permeability of a core changes with temperature, often increasing up to the Curie
temperature.
The Curie temperature is the critical temperature at which a core transfers from ferromagnetism to
paramagnetism.
In ferrite cores, the permeability begins to decrease upon formation by sintering and continues to
decrease with the lapse of time. In general, the rate of decrease is approximately linear with the log
of time and therefore becomes negligibly small in approximately a month after sintering.
The Inductance coefficient is defined as the self inductance per unit turn of a coil of a given shape
and dimensions wound on a magnetic core, and is determined by the formula:
L
AL  2
N
where L is the self inductance of the coil with core (Henries) and N is the total number of turns.
Ferrites were originally used as core materials in low-loss inductors. The property of ferrites that is
so useful for EMC is their frequency-dependent complex resistance. Consider ferrite beads. At low
frequencies, these devices present a low impedance, but at higher frequencies, the resistance rises
rapidly and the beads can be viewed as frequency-dependent resistors, which can be used to
suppress unwanted noise.
-FET
Field Effect Transistor.
Parameters. Not constant and will vary from point to point on the characteristic. Typical values are
given for a 2N3819.
ID
Mutual or transconductance  g m 
typical value = 4mA/V
 V GS
VDS
ID
Drain resistance  r d  1
where g d 
typical value = 30k
gd
 V DS
VGS
-FFT
Fast Fourier Transform. Allows time domain waveforms to be
examined within the frequency domain.
IPK06/05/17
-FHSS
Frequency Hopping Spread Spectrum. Used in WLANs in the
2.4GHz band. The data is transmitted within the 84MHz wide frequency band on continuously
changing carrier frequencies. The transmitter and receiver synchronously change the frequency
using a defined pattern. Narrow band interference cannot have a sustained effect on the
transmission because the transmission is repeated at different, interference-free part of the spectrum
if there is an error. FHSS has proven to be very resistant to RF interference. Also see DSSS.
-FIC
Fast Information Channel. Used in DAB
-FIFO
First In First Out
-Filters
Low Pass, Constant k  section
LK
CK
2
R
CK
2
LK 
High Pass, Constant k  section
R
fc
CK 
1
R f c
CK
2LK
LK 
2LK
R
4 f c
CK 
R
1
4R f c
Analysis of circuit below.
L
Vin
R1
C1
C2
R 2 Vout
Real:- R2·XC1·XC2·(R1·XC2·(XC1 - XL) + R2·XC1·(XC2 - XL))/Denominator
Im:- R2·XC1·XC2·(R1·R2·(XC1 + XC2 - XL) + XC1·XC2·XL)/Denominator
Denominator:R12 (R22·(XC12 + 2·XC1·(XC2 - XL) + (XC2 - XL)2) + XC22·(XC12 - 2·XC1·XL + XL2)) +
2·R1·R2·XC12·XC22 + XC12·(R22·(XC2 - XL)2 + XC22·XL2)
-FIR
Finite Impulse Response (filter)
IPK06/05/17
-Flash Memory.
Two types - NAND Flash and NOR Flash. NAND cells are about 40% smaller than NOR cells.
NAND architecture makes it suitable for use in sequential access applications, where large amounts
of data is read from sequential addresses. Nor architecture offers a faster random access time for
program code execution
-Flexray
An automotive communication protocol. Developed by Motorola,
Philips, BMW and DaimlerChrysler. The FlexRay system combines a scaleable static and dynamic
message transmission. Its protocol supports fault-tolerant synchronous, collision free bus access,
message latency and message-orientated addressing. It has a data rate of 20Mb/s. Claimed to be
10x faster than CAN.
-Flux Gate Magnetometer.
Used by the majority of modern electronic compasses. Relies on the principle of magnetic
saturation current to detect the presence, the direction and strength of a magnetic field. Originally
developed over 90 years ago and used in WW2 as a submarine detection device for submarines by
low flying aircraft. In essence, the design is based around the use of ferromagnetic core materials
with susceptibilities such that the earth's relatively weak magnetic field can produce something
approaching saturation. A primary coil is used to induce magnetic fields in opposite orientations
and a secondary or sense-coil outputs a signal to indicate the differences in the drive current needed
to achieve saturation in each direction. More sophisticated magnetometers use two cores and two
secondary coils (wrapped in opposite directions to induce fields with opposite orientations) are also
possible. Some disadvantages with this type of magnetometer - complex analogue signal processing
and high current pulses
-fMRI
functional Magnetic Resonance Imaging. Relies on the fact that more
oxygenated blood flows to active neurons than to those that are not working. There are slight
differences in the magnetic properties of oxygenated and de-oxygenated blood that are detected and
imaged. Resolution is around 2mm and an exposure of at least 10 seconds is required in which time
the patient must be absolutely still.
Field Oriented Control – sometimes called Flux Vector Control, is a
method that enables highest performance from permanent magnet, synchronous (or brushless servo)
motors throughout their speed range. FOC algorithms model the torque-generating efficiency of dc
motors and allow linear torque control
-FOC
-FOM
Figure of Merit.
-Fourier Transforms
Any continuous sequence of measurements or signal can be expressed
as an infinite sum of sine waves. Joseph Fourier proved his theorem in 1822 and produced an
algorithm known as a Fourier Transform for computing the frequency, amplitude and phase of each
sinusoid in that sum from measurements of the original signal.
-FOV
-FPA
Field of View
Factorised Power Architecture. Moves the isolation and power
conversion to the point of load in a system
IPK06/05/17
-FPAA
Field programmable Analogue Array
-FPC
Flexible Printed Circuits
-FPD
Flat Panel Display
-FPGA
Field Programmable Gate Array
-FPSC
Field Programmable SoC
-FPSLIC
Field Programmable System Level IC
-FPU
Floating Point Unit.
-FR4
The most common PCB substrate. It has a relative permittivity of
about 4 and cannot be heated above 300°C
-FRAM
Ferroelectric Random Access Memory. Non-volatile. In 1920
J.Valasek discovered that the polarisation of potassium sodium tartrate (Rochelle salt) could be
reversed by the application of an externally applied electric field. He discovered that there was a
hysteresis effect just like in ferromagnetism. Modern materials now include lead zirconium titanate
(PZT) and strontium bismuth tantalate (SBT).
-Free space attenuation Defined as the path between two isotropic radiators, one at each end
of the path.
An isotropic radiator is one which radiates uniformly in all directions. Placing such a radiator at the
centre of a sphere of radius r metres and radiating a power P, the power per unit area falling onto the
sphere is
P
Pa 
4π r 2
Numerically the gain of an aerial relative to an isotropic radiator is given by
4πA
G
λ2
where A is the effective area and  is the wavelength. An isotropic radiator, by definition, has a
gain of unity and so the effective area is
λ2
4π
Reverting to the sphere of radius r with an isotropic source radiating P watts at the centre. The
surface area is 4r2 and so intercepting the surface with an area of 2/4, the proportion of the
power radiated which is received by the isotropic aerial is given by
2
 λ 


 4 πr 
For a satellite, at a height of 500km, a radio transmission at 150MHz will have a loss of approx.
130dB. For a geostationary satellite at a height of 36000km, the attenuation at 150MHz would be
approx. 166dB
-FSK
Frequency-Shift-Keying
IPK06/05/17
-Fundamental frequency The lowest frequency in a periodic waveform. Also known as the first
harmonic.
-Fuses
Tinned copper wire.
swg
14
16
18
20
22
24
25
29
35
operating current
at 35oC (A)
33.3
22
12.2
6.8
3.5
2.5
2.1
1.0
0.33
rating as fuse
wire (A)
100
70
45
33
25
17
15
10
5
approximate
diameter (mm)
2.03
1.63
1.22
0.91
0.75
0.56
0.5
0.35
0.20
approx length per
200grams
7.1
11.4
20.2
34.6
50.9
01.3
114
234
717
Fuses often characterised their speed of operation.
Fast-blow (sometimes marked F) open quickly when the rated current is reached.
Ultrafast fuses (marked FF) are used to protect semiconductor devices.
Slow-blow fuses (often marked with a T) can tolerate a transient overcurrent condition, but will
open if the overcurrent condition is sustained.
HRC fuses (High Rupture Capacity) can break currents of 300,000A or more. Fuses for high
voltage equipment up to 115,000V are rated by the total apparent power (megavoltamperes, MVA)
of the fault level on the circuit.
Fuses with ceramic cases have a much higher voltage rating than glass fuses.
GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG
-GAL
Generic Array Logic
-GDT
Gas Discharge Tubes. Used as arresters. They operate as a voltage
dependent switch. When a voltage appears across the device that is greater than its break down
voltage (sparkover voltage), an arc discharge takes place within the tube which creates a low
impedance by which the surge current is diverted. When the transient has finished, the GDT will
reset to its non-conducting state, providing that the voltage of the system is below the holdover
voltage of the GDT. These devices can handle very large surge currents (5000A). Also available as
a fail safe device which incorporates a spring loaded switch which is normally insulated. Under
excessive conduction, the dissipated thermal energy causes the electrodes to get hot which destroys
the switch insulation so forming a short circuit.
-GFSK
-GMR
Gaussian frequency shift keying.
Giant Magneto Resistance - the effect observed in multilayer
structures of magnetic and non-magnetic alloys, where changes in the applied magnetic field causes
a large change in resistance.
IPK06/05/17
-GMSK
Gaussian Minimum Shift Keying. Modulation system for mobile
phones.
-GOT
Graphic Order Terminal.
-GOURIET
G. G. Gouriet - devised the same oscillator circuit as J. K. Clapp
independently.
-GPIB
General Purpose Interface Bus
GPRS
General Packet Radio Service. Provides an 'always on' data
connection. Users don't have to dial up and connection is instant. Billing is by the amount of data
received.
There are three classes of GPRS terminals
Class C - can operate in either circuit switched or packet switched mode, but the mode is manually
selected.
Class B - can operate in circuit switched mode and in GPRS idle mode at the same time. Can
receive data and then switch back to circuit switched mode quickly.
Class A - capable of full, simultaneous operation in circuit switched and packet switched modes.
GPS
Global Positioning System Transmitted on 1575.42MHz. Uses Lband signals from 24 orbiting satellites
Gray code
number by a single bit.
Decimal Number
0
1
2
3
4
5
6
7
8
9
10
11
12
12
14
15
-Ground loop
A code in which each Gray number differs from the preceeding
Hex Number
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
Binary Number
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Gray code
0000
0001
0011
0010
0110
0111
0101
0100
1100
1101
1111
1110
1010
1011
1001
1000
When two or more separate ground paths are tied together at
two or more points; the current circulating in the loop develops a voltage across any impedance
within the loop - thus, various points within a ground loop will not be at the same "ground"
potential.
IPK06/05/17
GSM
Global System for Mobiles Communication. European standard for
mobile phones. Digital mobile standard.
GSM850 824 - 849MHz for the uplink and 869 to 894MHz for the down link.
900MHz BT cellnet and Vodafone
1800MHz Orange and One Zone DCS-1800.
Parts of the US use 1900MHz.
GSM core clock frequency is 13MHz
Channel bandwidth - 200kHz
Raw channel bit rate - 270.833kbps
User bit rate - 14.4kbps
Modulation - GMSK
Block diagram of a typical GSM phone.
flash
memory
DSP
memory
ADSP
218xDSP
DMA
I/O
1-Mbit
SRAM
ARM7
controller
display
-GTLP
SIM
keypad
direct
conversion
radio
P.A.
baseband
I/Q, A/D, D/A
multiband
synthesizer
power
control
voiceband
codec
power management
battery charging
auxilliary
A/D, D/A
speaker
microphone
Gunning Transceiver Logic Standard.
-Guitar string frequencies
E
A
D
G
B
E
82.4Hz
110Hz
146.8Hz
196Hz
246.9Hz
329.6Hz
HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
-H1 Fieldbus
Used at the field level in industry to connect transmitters and
positioners. It is a two wire system operating at 31.25kb/s and has a maximum distance of1900m.
-HAL
Hardware Abstraction Layer
-HALT
Highly Accelerated Life Testing
-HARM
High Aspect Ratio Micromachining
-Harmonic
Signals which occur in integer multiples of the fundamental
frequency.
IPK06/05/17
-Harvard Architecture
Separate data memories and code memories
-HASS
Highly Accelerated Stress Screening
-HCI
Hot Carrier Injection - when 'hot electrons' are accelerated into the
dielectric layer in CMOS devices and damage the oxide layer
-HDD
Hard Disk Drive
-HDI
High Density Interconnect
-HDL
Hardware Design Language
-HDMI
High Definition Multimedia Interface. Competitor for DVI
-HDSL
High bit rate Digital Subscriber Line
-Helmholtz Resonator
3
V = volume of chamber in mm
D = diameter of sound emission hole in mm
L = length of sound emission hole in mm
f = resonant frequency of resonator in Hz
c = speed of sound in mm/s
c D
1
4
πV L  0.75D
For a closed organ type pipe, sealed with a speaker at the one end:θ
Vo
1
fo 
4(l  0.3d)
273
where fo = resonant frequency in hertz
Vo = velocity of sound in m/s
l = length of resonator in metres
d = diameter of resonator in metres
 = temperature in Kelvin.
f
-HID
High Intensity Discharge xenon headlamps. European regulators
require HID lighting to be equipped with automatic headlamp levelling systems.
-HIPERLAN
The ETSI standard for WLAN as compared to the IEEE 802.11a etc.
Type 1 has a frequency band of 5GHz with channel separation of 23.5MHz. The maximum raw
data rate is 23.5Mbps and has a single carrier. The modulation is FSK or GMSK. Only one carrier
per channel is allowed and the maximum power output is 30dBm.
IPK06/05/17
Type 2 has a 5GHz frequency band with channel separation of 20MHz. The maximum data rate is
54Mbps and the carrier type is OFDM. Modulation is BPSK and QPSK 16QAM or 64QAM.
There are 48data and 4 pilot carriers per channel and the maximum power output is 30dBm.
-HMI
Human Machine Interface
-HSCSD
High Speed Circuit Switched Data. Mobiles normally connect at
9.6Kbps. HSCSD boosts this by dispensing with error correction and by using more than one
channel at a time. In theory 43.2Kbps maximum. Only Orange at present support this and then only
at 28.8Kbps.
-HSDPA
High Speed Downlink packet Access - defined by the 3GPP. Boosts
3G data rates to 20Mb/s
-HSE
High Speed Ethernet.
-HUD
Head Up Display.
-HVAC
Heating, ventilation and Air Conditioning.
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII
-IAC
Integrated Access Device
-IBA
Intermediate Bus Architecture. The voltage is stepped down and then
stepped down again at the point of load.
-IC
Integrated Circuit. First built by Jack Kilby and Robert Noyce in
1958 at Texas Instruments. It won Kilby a Nobel prize and the two highest US science awards; the
National Medal of Science and the National Medal of Technology; only 13 people hold both.
John Hoerni, at Fairchild Semiconductors is credited with the mass production of ICs in 1959.
Geoffrey Drummer, a Ministry of Defence engineer, came up with the idea of ICs in 1952, but the
UK government did not persevere with the idea.
-ICA
Isotropic Conductive Adhesive. Developed as an alternative to
tin/lead solders.
-ICSP
In Circuit Serial Programming
-ICT
In Circuit Test
-IDE
Integrated Development Environment
-IDF
Intermediate Data Format
-iDTV
integrated Digital Television receiver
-IEC 60601
The safety directive series of standards relating to medical electronics.
IPK06/05/17
-IEC 61010-1
Defines four over voltage categories for voltage measuring
instruments. This defines how much electrical energy could be present during a transient and the
ability of the equipment to withstand a voltage transient.
-IEEE 802.11
Wireless LAN standard. Established in 1997. Further refined.
Transmitted in the 2.4GHz band with 25MHz channel separation for DSSS and 1MHz for FHSS.
Maximum raw data rate 2Mbps. Carrier type FHSS or DSSS. Modulation GFSK for FHSS and
DBPSK or DQPSK for DSSS. Number of carriers per channel is 79 with a maximum power output
of 30dBm
-IEEE 802.11a
Wireless LAN. OFDM in the 5.8GHz band. Three unlicenced
100MHz bands. 5.15 - 5.25GHz, 5.25 - 5.35GHz and 5.725 - 5.825GHz. Each band divided into 4
20MHz channels. Power output depends on band. 40mW (2.5mW/MHz) in the lower band.
200mW (12.5mW/MHz) middle band and 800mW (50mW/MHz) in the upper band. Up to 54Mb/s.
Carrier type is OFDM with modulation of BPSK and QPSK, 16QAM or 64QAM. 48 data and 4
pilot carriers are allowed per channel and maximum power output is 35dBm.
-IEEE 802.11b
Wireless LAN. Direct sequence in the 2.4GHz band. 11Mb/s over a
radius of 100m. 25MHz channel separation with a maximum data rate of 11Mbps. Carrier type is
DSSS and modulation is CCK. Only one carrier per channle is allowed and power output is
30dBm.
-IEEE802.11g
Wide band version of 802.11b
-IEEE802.3an
10GBase-T. 10GB/s Ethernet over twisted pair copper
54Mb/s using OFDM.
-IEM
Intelligent Energy Manager - from ARM. Manages frequency and
voltage scaling that adapts to the software application needs. This minimises the processor core's
power consumption while maintaining maximum processor performance.
-IGBT
Insulated Gate Bipolar Transistor
-IIR
Infinite Impulse Response (filter)
-IMD
InterModulation Distortion. In its simplest form it involves only two
signals that have been distorted such that it appears that the harmonics and fundamentals mix to
produce spurious frequencies. Consider a two tone signal consisting of frequencies of 7050kHz and
7051kHz. Intermodulation acts just as if harmonics on 14100kHz and 14102kHz were mixed with
these fundamental frequencies to produce outputs of 14102-7050 = 7052kHz and 14100-7051 =
7049kHz. Because these are caused by the curve relating input and output of an amplifying stage
having a cubic relationship, they are called third order products. Fifth order products at 7048 and
7053kHz as well as seventh order products on 7047 and 7054kHz may also be present.
-IMEI
-impedance
Unique identification number of a mobile phone.
The opposition of a circuit to the flow of an alternating current.
Measured in ohms. In its complex form Z = R + jX
IPK06/05/17
-IMT
Insert Mounting Technology
-Induction Motor
When a three phase supply is connected to the stator, a rotating
magnetic field is produced, which induces currents in the rotor. The current flowing within the
rotor produces the necessary torque. The rotors of ac induction motors fall into two categories,
squirrel cage and wound (or slip ring) rotors. Of the two, the squirrel cage is the most popular,
being simpler, more robust and efficient.
The squirrel cage rotor consists of solid bars, or rods, of copper or cast aluminium, connected
electrically and mechanically to end rings.
These conducting bars run parallel to the axis of the motor, and current flowing through them
creates the electromagnetic field needed for rotation. For motors that have to provide a high starting
torque two or three concentric rings of rotor bars may be used.
To concentrate the magnetic field in the rotor, the conductors are surrounded by a stack of steel
laminations, which gives the impression that the rotor is just a solid cylinder on a shaft.
The wound rotor also consists of a cylindrical core of steel laminations, but has insulated windings
instead of conducting bars. The windings are connected in a star configuration with the ends
brought out to three slip rings (for a three phase motor). The speed of a wound motor can be
controlled by series resistors, whereas the squirrel cage motor's speed cannot.
The speed of an induction motor depends on the number of poles built into it and the frequency of
the electrical power supply. The formula for the synchronous speed of an ac induction motor is
Speed = 60 x f / p (rpm)
Where f is the supply frequency in Hz and p is the number of pairs of poles.
-Inductors
Coil Winding Formulae.
The following approximations for winding rf coils are accurate to within about 1% for nearly all
small air-core coils, where
L=self inductance in microhenries
N=total number of turns
r=mean radius in inches
l=length of coil in inches
b=depth of coil in inches
Single layer wound coil
l
r
IPK06/05/17
L
rN 2
9r  10l
L9r  10l 
r
N
Multi layer wound coils
r
l
b
L
0.8 rN 2
6r  9l  10b
Single layer spiral wound
r
b
L
-INL
rN 2
8r  11b
Integrated Non-Linearity (DACs)
-International Distress Frequencies.
121.5, 243 and 406MHz.
-IPG
Rescur satellites COSPAS/SARSAT
Interactive Programme Guides. Use the Internet as a portal to see TV
programme listings.
-IRPA
International Radiation Protection Association.
Display radiation levels compared with occupational exposure limits.
Radiation Type
IRPA recommended limits
Levels measured at VDU screen
ELF
E:10kV/m
E:2V/m
50-60Hz
B:0.5mT
B:0.4T
VLF
E:614V/m
E:4V/m
3-30kHz
B:83T
B:0.1T
Microwaves
10-50W/m2
Undetected
2
IR
100W/m
Less than 10W/m2
UVA
104J/m2/8h
300J/m2/8h
2
UVB and C
1mW/m
Undetected
Airbourne ultrasound
100dB
68dB
Electrostatic
None specified
up to 15kV/m
-IS-136
Digital mobile phone standard using TDMA.
Channel bandwidth - 30kHz
Raw channel bit rate - 48.6kbps
User bit rate19.2kbps (analogue CDPD)
IPK06/05/17
Modulation II/4 DQPSK
-IS-95
Digital mobile phone standard using CDMA
-ISI
InterSymbol Interference
-ISM band
Industrial, Scientific and Medical radio band 2.4GHz
-ISO14443A
The international standard for contactless smartcards.
Operates at a frequency of 13.56MHz. MIFARE Interface Platform
-ISP
In System Programming
-ISP
Image Signal processor
JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ
-JEDEC
Joint Electronic Device Engineering Council
-jitter
the short term variation of a signal's significant instants from their
ideal positions in time.
-JTAG
Joint Test Action Group Established in the 1980s.
KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK
-Ku band
13.75 - 14.5GHz
LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL
-LCD
Liquid Crystal Display.
polariser
R
retardation film
G
B
liquid crystal
backlight
-LDMOS
RF power amps
TFTs
micro-reflective structure
Laterally Diffused Metal Oxide Silicon. Used in mobile phones for
IPK06/05/17
-LD-NL
Laser Diode - Non Linearity
-LED
White LEDs are difficult to produce. There are two main ways: either
mix the light from red, green and blue LEDs or use a phosphor coating to convert light from blue or
green LEDs into white light. The latter is called InGaN technology.
The colour temperature for current white LEDs start at 4000K and reach up to nearly 12000K, with
the most commonly found white LEDs being in the 6500K to 8000K. Cf 'daylight' for photographic
purposes is 5600K and most incandescent domestic lamps barely achieve 2500K.
The phosphor LEDs experience problems with the phosphor coating becoming depleted. This
brings a shift in the colour and loss of intensity as the epoxy lenses become milky due to the high
UV content of the light.
-LEPs
Light Emitting Polymers. Used in flexible displays.
-LGA
Land Grid Array - SMD packaging type
-Lighting levels
Recommended Illuminance levels.
Warehouse, storage bays, corridors and stairs
100 - 150 lux
General Office, rough bench or machine work
300 - 500 lux
Drawing offices and shops
750 - 1000 lux
Fine inspection
1500 - 3000 lux
Minute work
3000 - 5000 lux
-LILO
Last In Last Out
-LIN
Local Interconnect Network. The protocol used for peripherals within
vehicles. See CAN. The LIN protocol is a single master, multi slave bus that communicates via a
single wire. It serves low speed, low bandwidth (Class A:20kb/s) applications such as controls for
mirrors, seats, fans etc on a 12V single wire bus. The protocol is self synchronising and so enables
slave nodes to operate from a low cost RC oscillator.
-linear phase
The characteristic of a network whereby the phase of an
applied sine wave is shifted linearly with increasing sine wave frequency. A network with linear
phase shift maintains the relative phase relationships of harmonics in non-sinusoidal waveforms so
that there is no phase related distortion in the waveform.
-LIU
Line Interface Unit
-LLP
Leadless Leadframe Package. There are no leads extending beyond
the package body. The contact pads are exposed and flush with the bottom of the package
-LMIC
Linear Motor Iron Core
-LNA
Low Noise Amplifier
-LOA
Linear Optical Amplifier
-LOC
Lab On a Chip
IPK06/05/17
-lost motion
the condition in which an input to a mechanism yields no
corresponding displacement at the output. Not necessarily the same as backlash.
-LPCVD
Low Pressure Chemical Vapour Disposition
-LTCC
Low Temperature Co-fired Ceramic
-LTPS
-LUT
Low Temperature Poly-Silicon (TFT Displays)
Look Up Table
-LVD
Low Voltage Directive. Requires manufacturers to supply to market
equipment and products that do not create a danger.
-LVDS
Low Voltage Differential Signalling
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
-M2M
Machine to Machine communication
-MAC
Multiply Accumulate Units Used in DSPs
-Magnetisation curve
In a magnetic material that has been completely demagnetised,
the curve traced by the rising value of flux density B as a function of the field intensity H being
raised from the point of origin (0) is referred to as the Initial Magnetisation Curve.
If the field intensity is raised further, a point will be reached where the material becomes saturated
with flux and the curve levels off: the Saturation Flux Density, Bsat.
As the field intensity is reduced to zero from the saturation point, the flux density decreases and
settles at a certain value above zero. This value of remaining flux density is referred to as the
Remanence, Br.
To reduce the remanence to zero, the field intensity must be increased in the negative (reverse)
direction. The value of this reversed field intensity required for reducing the remanence to zero is
termed the Coercivity, HCB
B
Bsat
Hcb
0
H
Losses in the core consist of three components; hysteresis loss, eddy-current loss and residual loss.
IPK06/05/17
-Magnetron
Magnetrons for microwave heating are designed for CW operation at
a frequency of typically 2.450GHz. Water molecules try to align themselves with the electric field.
This changes millions of times per second and so the water molecules heat up. Older microwave
cookers operated at 2.375GHz.
-MBA
Module based Array
-MBES
MultiBeam Echo Sounders - used in the ScapaMap project
-MCH
Memory Controller Hub. See North Bridge IC
-MCM
Multi Chip Module
-MCP
Multi Chip Package
-MCU
MicroController Unit
-MDA
Manufacturing Defect Analyser
-MDP
Mask Data Preparation
-MELF
Metal ELectrode Face. Name often given to a surface mount resistor.
-MEMS
Micro ElectroMechanical Systems
-MEP
Media Embedded Processor - Toshiba - completely open and scalable.
-MET
Main Earthing Terminal
-Metal Detectors
Two physical effects are used for the detection of metal objects.
First, a metal object changes the self inductance of a coil and, if applicable, the degree of coupling
between two coils. The effect can be positive or negative, depending upon the material.
Diamagnetic r<1
Paramagnetic r>1 Ferromagnetic r>>1
Some materials and their magnetic properties.
Diamagnetic
Paramagnetic
Ferromagnetic
Bismuth
Aluminium
Cobalt
Glass
Silicon
Nickel
Copper
Air
Iron
Water
Platinum
Ferrite
Silver
Palladium
Steel
Second effect employed in the detection of metal objects is based on the eddy currents which are
generated when a conductor is subject to a varying magnetic field. The level of the eddy currents is
determined by the objects size and shape as well as the resistivity of the material. Strong eddy
currents will be induced on a metal sheet, but if slots are cut into the sheet the eddy currents are
much reduced
Common types.
BFO Beat Frequency Oscillator. A signal with a variable frequency is mixed with another signal
having a fixed frequency. The difference (or beat) frequency produced by the mixer is in the
IPK06/05/17
audible range. If the search head comes close to a metal object, the oscillator based on this coil will
change its frequency, resulting in a different tone which the user hears.
TR/IB Transmit Receive/Induction Balance. This method uses a transmitter as well as a receiver.
If a metal object comes within the search range of the search head, the degree of coupling between
the inductors is modified. This, in turn, produces a change in the oscillator output signal.
PI
Pulse Induction. Pulses are generated and transmitted. The intensity and the shape of the
received pulses provides an indication about the presence of metal objects within the scan range.
BFO metal detectors: The frequency of oscillation will change if the reactance of the search coil
changes at all. It is susceptible to capacitance and inductance changes. The capacitance changes are
due to changes in distance from the coil to the ground. This effect can be minimised by fitting a
Faraday screen to the coil. This is done by wrapping the coil with conductive foil which is
connected to the internal 'earth' of the oscillator. There should be a break in the foil so that it does
not form a short circuit turn. The sensitivity is unchanged, but the capacity effect of the ground is
reduced to negligible proportions. Another cause of spurious frequency change is heat - moving the
coil from sunshine to shade - can be reduced by thermal insulation of the coil.
To the search coil of a metal detector a piece of iron looks like a combination of two things:(a) a loosely coupled 'short circuit turn', since it conducts and loads the circuit
(b) an iron core, since it has permeability which tends to increase the effective inductance of the
coil.
These effects oppose one another. At 100kHz, the conductance effect is more important and so it
will not distinguish ferrous from non-ferrous metals. Modern metal detectors use audio frequencies
- down to about 1kHz. The permeability of a piece of iron is effectively greater and predominates.
At 100kHz, the skin effect restricts current flow to the metal surfaces - so all pieces of metal tend to
'look' similar if they are the same size and shape. At audio frequencies, the current penetration is
greater. It also allows the detector, by measuring the Q of the object, to identify the material.
Large metal objects cause a lowering of inductance due to eddy currents.
The sensitivity of a metal detector may well depend on:(a) the number of turns on the coil,
(b) the frequency of the reference and search oscillators.
To prevent oscillator locking, the reference oscillator can be operated at a (sub)-multiple of the
search oscillator.
-Meucci, Antonio
Now recognised as the inventor of the telephone instead of Alexander
graham Bell. First demonstrated his 'teletrofono' in New York in 1860. Worked in the same lab as
Bell
-MHP
Multimedia Home Platform - standard for interactive TV
-Microswitches
Small switches designed to be actuated by the physical motion of
mechanical devices. Typically rated at 1 - 10 million operations. Their durability is a natural
consequence of having a stiff metal strip inside which must be bent to activate the switch. The first
microswitch was invented by Peter McGall in 1932 in Freeport, IL. He was an employee of the
Burgess Battery Company at the time but started his own company Microswitch which was still
trading in 2005.
-MICS
Medical Implant Communications Service. Operates in a frequency
band of 402 to 405MHz.
-MIDI
Serial transmission at 31,250kBaud.
Transmission is via an opto-isolator, which ensures an absence of earth loops.
IPK06/05/17
Transmission is a 5mA current loop.
Need two leads, from OUT on one machine to IN on the second and then from OUT on the second
to IN on the first.
THROUGH OUT is just a buffered version of the signal entering.
Typical arrangement.
220R
+5V
TT–
220R
R+
R–
220R
T–
TT–
220R
THRU OUT
5
2
+5V
4
3
1
T–
220R
OUT
5
2
+5V
4
3
1
R–
IN
5
3
2
R+
4
1
16 different channels available numbered 1 to 16. Some devices require a fixed channel.
Modes:
Mode 1 - OMNI ON, POLY- the receiver recognises the messages of all channels and assigns to
voices polyphonically.
Mode 2 - OMNI ON, MONO- the receiver recognises the messages of all channels and controls
only one voice monophonically. One sound is emitted.
Mode 3 - OMNI OFF, POLY - the receiver will accept voice messages exclusively on the selected
channel and are assigned to voices polyphonically.
Mode 4 - OMNI OFF, MONO - Voice messages are recognised in the channels N through N+M-1,
and assigned monophonicallhy to voice 1 through M respectively. The number of voice M is
specified in the MONO MODE MESSAGE sent from the transmitter..
General Midi Instrument Patch Map. This list of instruments is organised into 16 'families', which
are Piano (1 - 8), Chromatic Percussion (9 - 16), Organs (17 - 24), Guitars (25 - 32, Basses (33 40), Ensemble (49 - 56), Brass (57 - 64), Reed (65 - 72), Pipe (73 - 80), Synth Lead (81 - 88), Synth
Pad (89 - 96), Synth Effects (97 - 104), Ethnic (105 - 112), Percussive (113 - 120) and Sound effects
(121 - 128).
1
Acoustic Grand piano
IPK06/05/17
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
Bright Acoustic piano
Electric Grand piano
Honky-tonk piano
Rhodes piano
Chorused piano
Harpsichord
Clavinet
Celesta
Glockenspeil
Music box
Vibraphone
Marimba
Xylophone
Tubular bells
Dulcimer
Hammond Organ
percussive organ
Rock organ
Church organ
Reed organ
Accordion
Harmonica
Tango accordion
Acoustic guitar (nylon)
Acoustic guitar (steel)
Electric guitar (jazz)
Electric guitar (clean)
Electric guitar (muted)
Overdriven guitar
Distortion Guitar
Guitar harmonics
Acoustic bass
Electric bass (fingered)
Electric bass (pick)
Fretless bass
Slap bass 1
Slap bass 2
Synth bass 1
Synth bass 2
Violin
Viola
Cello
Contrabass
Tremelo Strings
Pizzicato strings
Orchestrial Harp
Timpani
String ensemble 1
String ensemble 2
SynthStrings 1
SynthStrings2
IPK06/05/17
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
Choir Aahs
Voice Oohs
Synth voice
Orchestra hit
Trumpet
Trombone
Tuba
Muted trumpet
French Horn
Brass section
Synth Brass 1
Synth Brass 2
Soprano Sax
Alto Sax
Tenor Sax
Baritone Sax
Oboe
English Horn
Bassoon
Clarinet
Piccolo
Flute
Recorder
Pan flute
Bottle blow
Shakuhachi
Whistle
Ocarina
Lead 1 (square)
Lead 2 (sawtooth)
Lead 3 (calliope lead)
Lead 4 (chiff lead)
Lead 5 (charang)
Lead 6 (voice)
Lead 7 (fifths)
Lead 8 (bass + lead)
Pad 1 (new age)
Pad 2 (warm)
Pad 3 (polysynth)
Pad 4 (choir)
Pad 5 (bowed)
Pad 6 (metallic)
Pad 7 (halo)
Pad 8 (sweep)
FX 1 (rain)
FX 2 (soundtrack)
FX 3 (crystal)
FX 4 (atmosphere)
FX 5 (brightness)
FX 6 (goblins)
FX 7 (echoes)
IPK06/05/17
104
FX 8 (sci-fi)
105
Sitar
106
Banjo
107
Shamisen
108
Koto
109
Kalimba
110
Bagpipe
111
Fiddle
112
Shanai
113
Tinkle bell
114
Agogo
115
Steel drums
116
Woodblock
117
Taiko drum
118
Melodic Tom
119
Synth drum
120
Reverse Cymbal
121
Guitar fret noise
122
Breath noise
123
Sea shore
124
Bird tweet
125
Telephone ring
126
Helicopter
127
Applause
128
Gunshot
In addition to these instrument sounds, GM defines MIDI channel 10 as a percussion channel, with
each MIDI note number ('Key#') assigned to a different drum sound. This means that you can
assign an entire drum kit plus percussion to a single MIDI channel.
35
Acoustic bass drum
36
Bass drum 1
37
Side stick
38
Acoustic Snare
39
Hand clap
40
Electric snare
41
Lower floor tom
42
Closed HiHat
43
High floor tom
44
Pedal HiHat
45
Low Tom
46
Open HiHat
47
Low-mid tom
48
Hi-mid tom
49
Crash Cymbal 1
50
High tom
51
Ride cymbal 1
52
Chinese cymbal
53
Ride bell
54
Tambourine
55
Splash cymbal
56
Cowbell
57
Crash cymbal 2
IPK06/05/17
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
Vibraslap
Ride cymbal 2
Hi Bongo
Low Bongo
Mute Hi Conga
Open Hi Conga
Low Conga
High Timbale
Low Timbale
High Agogo
Low Agogo
Cabasa
Maracas
Short whistle
Long whistle
Short Guiro
Long Guiro
Claves
Hi Wood block
Low wood block
Mute Cuica
Open Cuica
Mute Triangle
Open Triangle
-MIMO
Multiple Input, Multiple Output. An aerial based technology that
increases speed, range and efficiency. By pushing more than one data stream of the same frequency,
no more bandwidth is required. MIMO is uncompressed signals, transmitted and received in a
single radio channel using multiple aerials on both sides of the wireless link. The aerials are smart
in that they use digital processing techniques to send and receive wireless signals using multiple
transmitters and receivers. Multiple aerials with signal processing and algorithms at both ends of
the link use the wireless signal reflections to strengthen the signals, instead of degrading them as in
other radio systems. Data rates of 108Mb/s can be achieved within a single 20MHz channel without
data compression. Some data compression actually reduces the bandwidth.
-MirrorBit cell
new flash memory cell technique from AMD
-MIU
Memory Interface Unit
-MLC
Multi-Level Cell
-MLCC
Multilayer Ceramic Chip capacitor
-MLP
Moulded Leadless Package
-MMAC
Million Multiply Accumulates
-MMC
Multi Media Card.
-MMF
Multi Mode Fibre
IPK06/05/17
-MMIC
Monolithic Microwave IC
-MMP
Mobile Media Processors
-MMS
Multimedia Messaging Services
-MOEMS
Micro-optical electro-mechanical systems. Also known as optical
MEMS and generally taken to include waveguides, diffraction gratings, moving mirror and moving
bubble devices.
-Morse code
A dit has a duration of a unit of time
A dah has a duration of three units
Elements of the same character are spaced one unit apart.
Characters are spaced three units apart
Words are spaced at least five units apart.
-MOSFET
Metal Oxide Semiconductor Field Effect Transistor. Each transistor
consists of a controlling gate of polysilicon separated from the underlying silicon by a thin layer of
silicon oxide insulation and partially overlapping two regions two regions called source and drain,
formed by doping the underlying silicon surface.
Applying a voltage to the gate creates an electrical field (hence field effect) that increases or
decreases, depending on its polarity, the population of the charge carriers in the channel, causing the
channel to either conduct or not conduct a current between source and drain.
Two mirror image kinds of MOSFET can be made in which source and drain are n-type doped and
the channel p-type, or vice versa. With an n-type channel, the charge carriers are electrons and a
positive gate voltage turns it on, while with a p-type channel, the carriers are positive 'holes' and a
negative voltage turns it on.
control voltage
gate
source
n-type
-MOST
drain
oxide
channel
p-type silicon
n-type
Media Oriented Systems Transport. Used in cars - fibre optic running
at 25Mb/s
-Motors
See DC motor
Motor Insulation:- Class F (155C), Class B (130C)
Industrial AC Induction motors spin at a speed governed by the number of motor poles and the
frequency of the alternating current. By controlling the frequency of the ac with a variable
frequency drive (VFD), the motor speed can be altered.
IPK06/05/17
VFDs typically convert a 480V, three phase ac source to dc which is then switched at up to 20kHz
using IGBT-based electronics.
-MOV
Metal Oxide Varistor. Provides an over voltage fault
protection system
-MPEG-2
The format for standard definition television. Has data rate of
between 2 to 8Mb/s. This requires about 2GB of storage per hour. Recorded using Variable Bit
Rate where the bit rate varies depending upon the content of the video
-MPSL
Multi-Protocol Switch Label
-MPSOC
MultiProcessor System On Chip
-MRAMs
Magnetic Random Access memories. Magnetic memories. See MTJ
-MRI
See fMRI
-MRS
Master Resynthesis System
-MSL
Moisture Sensitivity Level
-MSPP
Multi Service Provisioning Platform - the interface between a MAN
operated by a service provider and an organisation's network
-MSPS
Millions of Samples Per Second
-MTBF
Mean Time Between Failure
-MTCMOS
Multi-Threshold CMOS
-MTD
Memory Technology Driver - used in NAND Flash memory
-MTJ
Magnetic Tunnel Junction. Uses half metal ferromagnetic materials
to create perfect on/off switches. The material is a 96% spin polarised chromium dioxide single
crystal film.
-MUD
Multiple User Detection. Used with W-CDMA. Multiple user are
tracked and their signals are removed from each others signals.
-MUI
Multiple User Interface.
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
-NAND Flash Memory High cell densities and high capacity. No XIP. Has inherent bad
blocks. Uses blocks of 512Bytes which are called pages. Prone to low reliability.
-Nanometre
IPK06/05/17
One billionth of a metre
About 10 hydrogen atoms
About 5 silicon atoms
The distance that a finger nail grows in one second
One hundredth the diameter of a typical bacterium
One tenth the thickness of the metallised layer on a crisp packet.
One 80,000th the thickness of a human hair
-Nanotechnology
The art and science of manipulating materials and objects of size 1nm
to 100nm
-NAV
Network Allocation Vector. 802.11a
-NCO
Numerical Controlled Oscillator
-Neural Networks
Lotus cars - sound cancellation system and active valve train systems
-NEXUS
Network of Excellence in Multifunctional Microsystems. Established
in 1992 with European Union funding, it is now a non-profit making association with headquarters
in Grenoble, France, with the aim of providing access to information and guidance on MEMS.
www.nexus-emsto.com
-NFC
Near Field Communication. eg RFID
-NFS
Network Filing System
-NoC
Network on a chip. Connects the IP blocks within the SoC with a
packet based paradigm with a layered protocol stack that replaces the traditional circuit switched
bus
-Noise
Any random interference to the signal of concern
-NOR Flash Memory
XIP capabilities and high read performance. Expensive per megabyte
Used in low capacities - 1 - 4MB. Has poor write and erase performance.
-North Bridge IC
Now called the Memory Controller Hub (MCH) which serves to
interface memory and graphics to the high-speed CPU bus
-NRE
Non-Recoverable Expenses
-NRE
Non Recurring Engineering
-NROM
Nitrided Read Only Memory
-NRZ
Non-Return-to-Zero. A common digital pattern in which the
waveform switches to a "1" when a valid bit occurs in the cyclt and stays at that value until the next
cycle boundary, assuming that the cycle originated with a binary "0"
IPK06/05/17
-NSF
New Stream Format
-NTSC
National Television Standards Committee. American video standard.
Videos play at 30 frames per second.
-Nyquist Sampling Theorem.
Requires that a signal be sampled at a minimum rate equal to twice the maximum input signal
frequency for faithful reproduction. Sampling below this frequency will lead to aliasing.
OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
-OAI
Off-Axis Illumination.
-OCV
On-Chip Variation
-ODS
Ozone Depleting Substances.
-ODT
On Die Termination
-ODVA
Open Devicenet Vendor Association. Industrial Ethernet connectors.
-ODT
On Die Termination
-OEM
Original Equipment Manufacturer
-OFDM
Orthogonal Frequency Division Multiplexing (or Modulation). Also
referred to as multi-carrier or discrete multi-tone modulation. Utilises multiple sub-carriers to
transport information from one user to another. An OFDM system divides a high speed serial
information signal into multiple lower speed sub-signals that the system transmits simultaneously at
different frequencies in parallel. OFDM is the basis for ADSL and digital audio broadcasting.
-OGSA
Open Grid Services Architecture
-OHCI
Open Host Controller Interface
-OLAP
On Line Analytical Processing.
-OLED
Organic LED. Discovered in 1987 by Ching Tang and Steve van
Slyke of Eastman, Kodak.
Magnesium Silver Alloy: cathode
Aluminium Hydroxyquinoline (ALQ): N-type
Naphthaphenylene Benzidine (NPD): P-type
Copper Phthalocyanine: passivated ITO and provides stability.
Indium Tin Oxide (ITO): emitter
Glass or polymersubstrate
-OOK
On-Off Keying
IPK06/05/17
-OPB
On chip Peripheral Bus
-OPC
Optical Proximity Correction
-Optical fibre
Work first started in 1960 when it was realised that the
demand for telephones would deplete the capacity of copper cabling. The developments were first
announced in January 1966 when Dr Charles Kao and George Hockham presented a paper at an IEE
meeting in London. Their findings demonstrated that the experimental optical waveguide had an
information carrying capacity of one Gigacycle - equivalent to about 200 TV channels or 200000
telephone channels. Their experiments using glass tubes initially resulted in data losses of around
1200dB/km over 20m, but this they attributed to impurities in the glass.
In 1970, glass maker Corning developed glass tubes with far less impurities. Three years later BT
ran a trial fibre optic link alongside its conventional copper network from Hitchen to Stevenage in
Hertfordshire using fibre cables made from Corning's glass. It found that this reduced data losses to
25dB/km.
By the 1980s, the first undersea trials between the UK and Belgium were under way and carried data
at 50Mbps. Laser technology also developed until by 2000 cables with data losses of 0.2dB/km and
data rates of 1.6Tbps are available.
-Oscillators
Using tuned circuits
Hartley.
+Vs
Vout
0V
Colpitts.
+Vs
Vout
0V
Clapp or Gouriet
IPK06/05/17
+Vs
Vout
0V
Franklin (and Butler)
Vackar
-OSD
Object Sequence Diagram
-OTP
One Time Programmable.
-OVL
Open Verification Library - www.verificationlib.org
-OXC
Optical Cross Connect.
PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPP
-Packet Switching
Data streams are broken up into packets and each packet is routed to
its destination over a shared medium. See Circuit Switching.
-PAL
Phase Alternating Line. Videos play at 25 frames per second.
-PBM
Peripheral Bus Module
-PCDE
Peak Code Domain Error
-PCI
Peripheral Components Interconnect.
-PCM
PhotoChemical Machining
-PCS
Polymer Clad Silica. Used as an alternative to POF and allows higher
temperatures
-PDC
Personal Digital Cellular - mobile phone system used only in Japan.
-PECL
Positive Emitter Coupled Logic
-PEF
Photo ElectroForming
-PEM fuel cells
Polymer Electrolyte Membrane fuel cells. Proton Exchange
Membrane. Hydrogen is passed over one side of the PEM and Oxygen (air) over the other side. In
linking to form water vapour, negative ions are produced which are captured by the membrane.
-PER
Packet Error Rate
IPK06/05/17
-Permanent Magnets
Compression moulded neodymium-iron-boron (NdFeB) for the highest levels of magnetic flux
density in simple shapes like rings, disks or cylinders.
Injection moulded NdFeB, when complex shapes are needed or when assembly costs can be reduced
using insert or over-moulding techniques.
Sintered aluminium-nickel-cobalt (AlNiCo) is the best choice where magnetic properties must
remain stable, especially at eleviated operating temperatures.
In the same circumstances samarium-cobalt (SmCo) also outperforms NdFeB
-PES
Photo-enforced Stratification
-PET
Positron Emission Tomography. Relies on the fact that more
oxygenated blood flows to active neurons than to those that are not working. Water containing a
tiny amount of positron emitting )xygen 15 is injected into the blood stream. Where there is more
flow, there will be more positrons given off. The resolution of PET is about 7mm. A 30 second
exposure is needed for PET in which time the patient must be absolutely still.
-PFC
-Photocopier
Power Factor Correction
Invented by Chester F. Carlson
-PIC
Programmable Interface Controller. Originally made by Arizona
Microchip. Based on a RISC architecture - there are only around 40 different instructions.
-PID
Proportional-Integral-Derivative. Such a controller tracks the errors
between the process variable and the set point, the integral of recent errors and the rate by which the
error has been changing. It computes its next corrective action from a weighted sum of those three
terms (or modes), then outputs the results to the process and awaits the next measurement.
A PID using the ideal form of the PID algorithm computes its output CO(t) according to the formula

1
 et dt   TD  d et 
CO( t )  Pe( t ) 
TI
 dt


CO(t) is the controller's current output
e(t) = SP-PV(t) is the error between the set point (SP) and the process variable PV(t).
P is the controller gain
TI is the integral time
TD is the derivative time
The controller gain refers to the amount by which the error signal will gain or lose strength as it
passes through the controller en route to becoming part of the controller's output. A PID with a high
gain will tend to generate aggressive corrective actions to eliminate errors.
A PID controller with a long integral time is more heavily weighted towards proportional action
than integral action.
A PID with a long derivative time is more heavily weighted towards derivative action than
proportional action.
The first feedback controllersincluded just the proportional term and tended to drive the error
downward to a small but non-zero value and then quit. When the integral term was added, it was
sufficient to augment the proportional action just enough to eliminate the remaining error. The
derivative term was added as a 'rate control'.
IPK06/05/17
Tuning a PID controller involves selecting values for the tuning parameters P, TI and TD, so that
the controller will be able to eliminate an error quickly without casuing the process variable to
fluctuate excessively. It is found that the best choice for each of the tuning parameters depends
upon the value of the other two.
Ziegler-Nichols tuning methods.
Open loop technique. The controller is taken off line and the process is manually made to increase
its output abruptly. A graph of the resulting output is obtained.
T
d
K
time/s
d is the dead time - its initial reaction to the step change.
T is the process time constant
K is the process gain.
By experiment Ziegler-Nichols determined that the best settings for the tuning parameters were:P = (1.2 x T)/(K x d)
TI = 2.0 x d
TD = 0.5 x d
The closed loop method is set up with the controller in automatic mode but with the integral and
derivative actions shut off. The controller gain is increased until even the slightest error causes a
sustained oscillation in the process variable. The smallest controller gain that can cause such
oscillation is called the ultimate gain PU. The period of those oscillations is called the ultimate
period TU. The tuning parameters then become:
P = 0.6 x PU
TI = 0.5 x TU
TD = 0.125 x TU
-Piezo Electric
Discovered in the early 1880s by Pierre Curie. Gtes its name from
pressure electricity. Property of some cyrstalline materials including quartz, Rochelle salt,
tourmaline and manufactured ceramics like Barium Titanate and Lead Zirconate Titanates (PZT).
When mechanical pressure is applied to one of these materials, the crystalline structure produces a
voltage proportional to the pressure. Conversely, when an electric field is applied, the structure
changes shape producing dimensional changes in the material. Useful for switches since a
movement of about 10mproduces a usabble switching voltage or charge.
-PIU
Parallel Interface Unit.
-PLC
Power Line Communication. Using mains cables between substation
and subscriber house. Uses the 2 – 30MHz bands.
-PLC
Programmable Logic Controller
IPK06/05/17
-PLD
Programmable Logic Device
-PLM
Product Lifecycle Management
-PMSM
Permanent Magnet Synchronous Motor
-PNO
Profitbus Nutzer Organisation. Industrial Ethernet connectors.
-PoE
Power over Ethernet. IEEE 802.3af
-POF
Plastic Optical Fibre. Used as the physical layer in car systems.
Offers a high bandwidth and high immunity to EMI and is light in weight. However, it does not like
high temperatures.
-Polarisation
Radio waves consist of two coupled fields perpendicular to each
other, one electric and one magnetic. The position and direction of the electric field with reference
to the earth's surface (the ground) determines polarisation. The most common are:Horizontal - field parallel to the ground.
Vertical - field perpendicular to the ground
Circular - the field is spinning, covering all possible angles
-POL
Point of Load. Where the voltage regulator is placed very near to the
load. Particularly useful when the load draws high current at low voltage.
-POR
Power On Reset
-POTS
Plain Old Telephone Service
-PPTC
Polymeric Positive Temperature Coefficient. These devices are
widely used for IEEE 1394 applications, providing resettable circuit protection on computers,
peripherals and portable electronics.
-PRC
Primary Reference Clock
-PRM
Pre-regulator module. Used in IBA systems.
-PSD
Position Sensitive Device
-PSD
Programmable System Devices.
-PSK
Phase Shift Keying
-PSM
Phase Shift Mask
-PSoC
Programmable System on a Chip
-PSRAM
Pseudo Static Random Access Memory
IPK06/05/17
-PSRR
Power Supply Rejection Ratio
-PVR
Personal Video Recorders
-PWM
Pulse Width Modulator
-PXI
PCI eXtensions for Instrumentation. Taking over from VXI and
GPIB
-PZT
Lead Zirconate Titanates. A piezo electric material.
PZT Perovskite materials can allow capacitors with densities over 30nF/mm2 to be fabricated.
These compounds offer a high dielectric constant of approximately 900, which is around 200 times
that of silicon dioxide.
QQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQQ
-QAM
Quadrature Amplitude Modulation.
-QDR
Quad Data Rate
-Q factor
Quality factor of a tuned circuit oscillating system. Derived from the
'logarithmic decrement' of the circuit.
1 L
It can be shown for a series LCR circuit that Q 
R C
1
1
 L
Since 0 
=> Q 
 0
R
0 CR
LC
where 0 = 2  f0,
f0 = the resonant frequency.
Also Q  f o where fo is the resonant frequency and f is the bandwidth where zmax/2
f
-QFN
Quad Flat devices No leads
-QFP
Quadrature FlatPack
-QPSK
Quadrature Phase Shift Keying
-Quadrature Modulation (IQ) modulation. Used in digital wireless communications. Two
carriers - an in-phase (I) waveform and a quadrature-phase (Q) waveform that is delayed by exactly
90 degrees relative to the "I" waveform - are modulated to produce four states of information. The
two carriers are combined and transmitted over one channel, then separated and demodulated at the
receiving end. The IQ format delivers far more information than other forms of analogue and
digital modulation: it increases the effective bandwidth of the system.
-Quantum Dot
A tiny volume of semiconductor inside a device (eg LED) which can
capture a small number of electrons and holes. When a voltage is applied to the dot, the electron
and hole combine to emit a photon.
IPK06/05/17
-Quatrans
Quasiparticle Trapping Transistors or QTs. Super conducting
transistor.
-Quartz crystals
The 'AT' thickness shear resonator is often used.
A round quartz 'blank' is cut from either Natural or high Q-factor cultured quartz at a
crystallographic orientation chosen to give minimum frequency variation over a wide temperature
range.
The blank is lapped to a thickness for the required natural resonant frequency, is chemically etched
to improve the surface finish, so improving its activity and stability.
Further etching by means of ion bombardment is employed in some cases, before depositing silver
or gold electrodes onto the quartz by thin film evaporation techniques, under high vacuum.
The accurately aligned electrodes conduct electrical energy to the system and their mass is utilised
to trim the frequency to the exact final requirement.
The crystal is bonded to the mounting system which is designed to keep energy losses to a minimum
while at the same time providing protection against mechanical shocks. The terminations of this
system are fed through an hermetic glass to metal seal.
After final adjusting, washing and baking, the holder is soldered to the base. The unit is evacuated,
filled with a dry inert gass, and hermetically sealed. This protects the crystal from chemical and
climatic influences and assures the best long term stability.
Equivalent circuit near resonance.
C1
R
L
C0
L is the dynamic inductance and represents the electrical equivalent of the vibrating mass of the
electromechanical oscillations and is usually expressed in milliHenries.
C1 is the dynamic capacitance and is related to the dynamic inductance by the expression
C1 = 1/2L
It represents the elasticity of the blank and is very small and usually expressed in femptoFarads.
R is included to represent the energy loss from the quartz (self heating and acoustic losses).
C0 is primarily the static capacitance between the two electrodes, with the quartz acting as a
dielectric.
At the Series Resonant frequency, fs, the reactance of L and C1 is cancelled and the resistance is a
minimum. As the frequency increases from this point, the motional arm becomes more and more
inductive and Parallel Resonance, fp occurs when the reactance of the motional arm is equal to the
reactance of the shunt capacitance. This is the high impedance resonant condition.
The addition of an external capacitance, CL, effectively modifies the shunt capacitance in the
equivalant circuit and therefore alters the parallel resonant frequency. This is why it is important to
accurately specify the load capacitance of the circuit into which the crystal is to be placed.
The Q value of the circuit is
Q = L/R
For discrete component LCR circuits, Q values in the order of a few hundred are typical. For a
crystal, values of 105 and easily obtained.
The addition of an external load capacitance, CL will increase (pull) the resonant frequency
according approximately to the following
IPK06/05/17
df
C1

f
2C0  CL
The pullability of the crystal is proportional to its C1. A large C1 gives a good pulling range but
pooer frequency stability.
RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR
-RADAR
As used by the police and emergency vehicles.
Anti collision radar 5.8GHz - unlicensed band.
X-band
9.14GHz, 9.9GHz, 10.525GHz + 50MHz
Ku-band
13.45GHz
K-band
24.125GHz, 24.150GHz + 100MHz
Ka-narrow band
34.0GHz, 34.3GHz, 34.7GHz
Ka-broad band
33.4 - 33.6GHz
LTI 20-20, Pro and UltraLyte Laser
275 - 300THz
-Radio Licence exempt bands
In Europe - 868MHz US equivalent 915MHz
-Rake Receiver
Is often used to despread a signal after it has been subjected to a
multipath channel. It is a commonly used to counter the effects of RF multipath fading due to
atmospheric absorption, ionospheric reflection and refraction and reflection from terrestrial objects
such as mountains and buildings. The technique uses several sub-receivers, each delayed slightly, in
order to tune in the individual multipath components and then combine them to optimise the signal
reception.
Price and Green invented the technique in 1958. The 'rake' nomenclature derives from the method
of reception that involves the use of several correlators, each one of which can be thought of as a
finger, or tine of a garden rake.
-RAP
-RCCB
30mA
10mA
100mA
Reconfigurable Algorithm Processor
Residual Current Circuit Breaker.
general protection
reduced shock protection
fire protection
-RCD
Residual Current Device. Protect people from harm from electric
shock and also protect equipment and cabling from the risk of fire caused by fault currents passing
to earth. RCDs work on the current balancing principle - all the current flowing from the supply on
the phase wire to the load must return to the supply on the neutral wire. An RCD is placed in line
with the phase and neutral supply to the load. Should it detect any imbalance, it removes the supply
from the load in a few milliseconds at a given fault current level (often 30 or 100mA). RCDs do not
detect over current and so must be used with circuit protection devices.
-RCE
Regional Code Enhancement - stops DVDs being played on hacked
machines
-RCU
Reconfigurable Communications Unit. Used in routers.
IPK06/05/17
-Reciprocal Mixing
Occurs when the output of a local oscillator is noisy or as FM. This
creates a number of signal within the pass band of the IF which can then interfere with each other.
It can also lead to a reduction in receiver sensitivity.
-Rectifier
Also see Voltage doublers
Half wave
+1.4V
+
V
0V
Full wave
+1.4V
+
V
0V
Three phase full wave
+V
Three
Phase
Supply
+
0V
-Regenerative receiver
Positive feedback is used with a tuned circuit to set the circuit on the
point of oscillation - so increasing the Q and amplification, while decreasing the bandwidth.
-RETs
Resolution Enhancement Techniques. Three main ones:-(OPC)
Optical Proximity Correction; (PSM) Phase Shift Mask; and (OAI) Off-Axis Illumination
-RFC
Rotor Flux Control. Provides a combination of dynamic performance,
stability and speed accuracy without encoder feedback.
-RF Formulae
Field Strength (far field)
Eo = (30PiGa)½/d
Transmit Power
Pi = [(Eo2)(d2)]/30Ga
Peak Voltage on AM carrier Ep = (Eum)(1 + AM/100)
where
Eo = field strength in volts/metre
Pi = incident power at the aerial in watts
Ga = numeric aerial gain (10(dBi/10))
IPK06/05/17
Ep = peak voltage of the modulated carrier
Eum = unmodulated rf voltage
dBi = aerial gain referenced to an isotropic radiator (a theoretical point source
radiator with uniform spherical coverage and no losses)
-RFID
Radio Frequency Identification. Tags attached to items to track
movement. Two types. Active and Passive. Active RFID tags are powered by an internal battery
and are typically read/write. Some active tags can have up to 1MB of memory. Passive RFID tags
obtain their power from the reader. Tend to have shorter range, lighter and less expensive. Require
higher power reader. Several frequency ranges. Short range operate from 30 to 500kHz. Tend to
be used in security access. High frequency ones 850 - 900MHz and 2.4 - 2.5GHz offer long read
ranges - greater than 30m and high reading speeds.
124 - 134kHz
Widely used
Limited read range.
13.56MHz
In wide use
Poor performance near metal.
865-868MHz
Newly licensed by Ofcom - but not widely used by other countries.
868 - 928MHz
Long read range
Detuning possibilities
2.45GHz
Long read range
Not accepted in Europe.
-RIAA
Recording Industry Association of America
-RIO
Reconfigurable I/O
-rise time
The time taken for the leading edge of a pulse to rise from its low to
its high value, typically measured from 10% to 90%.
-RKE
Remote Keyless Entry - used on cars.
US and Japan use 315MHz Europe - 433.92MHZ (ISM band).
In Japan FSK is used - elsewhere ASK is used.
Often 64 or 128 bit data streams are used.
A keyfob usually issues 4 x 10ms data streams in succession. A receiver usually polls every 20ms
and expects to decode two complete data streams.
-RMS
Root Mean Square. The RMS value of an alternating waveform is
equivalent to the direct value that would produce the same heating in a resistive load.
-RNC
Radio Network Controller
-RoC
Radio on a Chip
-RoF
Radio over Fibre
-RoHS
Removal of Hazardous Substances directive. Will increase the
recycling of electronic equipment. The directive bans lead, mercury, cadmium, hexavalent
chromium and flame retardants in electronic equipment
Restriction of certain Hazardous Substances - due to be implemented in the summer of 2006
-RCC
ReConfigurable Computing. Used for debugging complex ICs
IPK06/05/17
-RoHS
Restriction of Hazardous Substances. The RoHS Directive
2002/95/EC comes into force on 1st July 2006 and restricts the use of certain hazardous substances
in electronic and electrical equipment within the European market.
There are six restricted substances and their allowed level:
Cadmium (Cd)
100ppm(0.01%)
Lead (Pb)
1000ppm(0.1%)
Mercury (Hg)
1000ppm(0.1%)
Hexavalent Chromium (CrVI)
1000ppm(0.1%)
Polybrominated Biphenyls (PBB's)
1000ppm(0.1%)
Polybrominated Diphenyl Ethers (PBDE's)
1000ppm(0.1%)
The directive does allow provision for some specific exclusions such as lead in glass and ceramics
etc. Equipment used for military and medical purposes, together with monitoring and control
instrumentation, are also excempt.
-RSA
Recognised Spectrum Access
-RTL
Register Transfer Level
-RTOS
Real Time Operating System
-RTS
Resistive Touch System
SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS
-SACD
Super Audio CD. Uses DSD, Direct Stream Digital technology
compared with Pulse Code modulation on normal CDs.
CD
SACD
Disc diameter
12 cm
12.cm
Disc thickness
1.2mm
1.2mm
Data capacity single layer
740MB
4.7GB
Data capacity dual layer
n/a
8.54GB
Maximum running time
74 mins
100min (single layer, two channel)
Max number of tracks
99
256
Frequency range
DC to 20kHz
DC to >100kHz
Dynamic range
96dB
>120dB (audible range)
Other information
audio, text
text, audio, graphics, video
Standard CDs encoded at 16-bit resolution and a sampling frequency of 44.1kHz. DSD samples at
2.8224MHz, storing the sound as single bit data. Water marked to reduce piracy. If the CD cannot
read the water mark it is rejected.
-sampling
the conversion of a portion of an input signal into a number of
discrete electrical values for the purpose of storage, processing and /or display by an oscilloscope.
-SAR
-SAR
Segmentation and Reassembly
Specific Absorption Rate. The electric field is measured in a volume
of liquid of a given permittivity and conductivity.
IPK06/05/17
SAR 
 E2

where  is the conductivity of the medium and  is the density of the medium. Units are Watts/kg
and measured values are averaged over prescribed volume masses, namely 1g and 10g. The normal
limit is 2W/kg in 10g average mass.
-SAR
Synthetic Aperture Radar.
-SARAM
Sequential Access Random Access Memory.
-SAW
Surface Acoustic Wave filter. A SAW filter works by etching an
inter-digitated comb pattern into a crystal of a piezoelectric material, typically lithium niobate. An
electric signal entering the chip is converted into an acoustic wave that travels along the surface of
the crystal from one comb to the other. The comb structure is designed to obstruct waves outside
the frequency of interest, which is converted using the piezoelectric effect back into an electrical
signal. The smaller the teeth on the crystal, the higher the frequency the SAW filter can work with.
An array of thin metal electrodes deposited at fractional wavelengths apart on a polished
piezoelectric substrate. A RF signal applied to the electrodes excites a surface acoustic wave over
the device which resonates at a frequency determined by the distance between the inter-digital metal
electrodes
-SBC
Single Board Controllers.
-Schottky Diode Balanced Mixers.
SBL-1
SBL-1X
SRA-1
SRA-3
SRA-1H
SRA-2C
SRA-11
1 - 500MHz
10 - 1000MHz
0.5 - 500MHz
0.025 - 200MHz
5 - 500MHz
5 - 1000MHz
5 - 2000MHz
8
1
5
3
6
4
7
2
-SD
Secure Digital – removable memory storage card
-SDR
Software Defined Radio
-SED
Solvent Emission Directive. From the European government. Limits
the emission of such solvents
IPK06/05/17
-SED
Surface-conduction Electron-emitter Display. Canon and Toshiba.
Uses the collision of electrons with a phosphor coated screen to emit light – as in a CRT. The
electron emitters are distributed equally to pixels on the display. This creates a high brightness,
high definition display, together with a high image quality, fast video response performance, high
contrast, high graduation levels and low power consumption.
-SEE
Single Event effects (radiation effects on components)
-Selectivity
Within a radio system, the ability to extract a wanted signal from a
band containing many signals. Selectivity assessment would include measuring filter shape factors
and their degradation by reciprocal mixing.
-SEMI
Semiconductor Equipment and Materials International
-Sensitivity
Within a radio system, the input signal level required for the receiver
to produce, say, a 10dB signal to noise ratio at the output, under ideal conditions with no other
signal present.
-SEPTIC
Single Ended Primary Inductance Converter
-SERCOS
Serial Real Time Communication Systems
-Serial Data transfer.
parity
P
stop start D0 D1 D2 D3 D4 D5 D6 D7 P
lsb
stop
D0 D1
msb
-SEU
Single Event Upset
-SFDR
Spurious Free Dynamic Range
-SFR
Special Function Register
-SIM
Subscriber Identification Module
-SIMD
Single Instruction Multiple Data
-SiP
System in Package. Uses IC processing technology to create high
density substrates capable of integrating multiple IP blocks with single package components.
-SIU
Serial Interface Unit.
-SLM
Spatial Light Modulator
-SMPS
Switched Mode Power Supply. Advantages: cheap, lightweight,
portable. Block diagram shown below for a standard SMPS.
IPK06/05/17
IN
EMI
filter
rectifier &
smoothing
transformer
output
driver
clock
S
latch
R
current
sense
comparator
feedback
error
amp
reference
voltage
A common pulse width modulator module is the UC3845. It is used as in the circuit below:
Rstart
+
Rt
IN
EMI
filter
rectifier
UC3845
Rg
+
smoothing
+
Ct
+
+
Cf
Rf
Rsense
Rstart supplies power during the first mains application. Once the IC oscillates and energises the
transformer, the auxillary winding takes over and powers the IC. The circuit monitors the primary
current cycle by cycle through Rsense. Rf and Cf filter this signal. Rg slows down the transitions
of the MOSFET and so reduce radiated noise.
The mains input is first rectified and then smoothed, followed by the the transformer and primary
side of the switch together with the primary side controller which varies the duty cycle of the switch
in response to the feedback signal, which in turn is fed back from the secondary side. Flyback
SMPS can operate in two modes: Discontinuous and Continuous. When the electronic switch turns
on, a voltage is applied across the transformer primary. Since at this time the secondary diode is
off, the transformer behaves like an inductor. Current will ramp-up through the primary as energy is
stored in the magnetic flux. When the switch turns off, the secondary diode turns on, the current
through the secondary ramps down, whilst the energy is transferred to the secondary side bulk
capacitor. Since the current through the magnetising inductance drops to zero, this is a
Discontinuous conduction mode. If the magnetising current does not drop to zero, then the system
is running in Continuous conduction mode. Discontinuous mode has smaller inductance and so
smaller snubber losses and does not require a fast recovery diode, whereas Continuous mode has
smaller peak currents causing lower switch losses and lower transformer losses.
Efficiencies - 75 to 95%
Buck SMPS - step down
Boost SMPS - for step up
SEPIC - Single Ended Primary Inductance Converter - when input and output voltages are similar.
Flyback SMPS - for higher power outputs
IPK06/05/17
-SMT
Surface Mounted Technology
-SMU
Source Measure Unit. Fancy power supply
-SOA
Semiconductor Optical Amplifier - a semiconductor based amp often
integrated with both fixed frequency and tuneable lasers
-SoC
System on Chip
-SOHO
Small Office Home Office
-SoI
Silicon on Insulator. Technique for producing very small transistors -
50nm thick.
-Solder
Lead free:
Tin/Silver (Sn-3.5Ag) melting point 221°C
Tin/Silver/Copper (Sn-3.8Ag-0.7Cu) melting point 217°C
-Soliton
Single waves that do not disperse over distance
-SOPC
System On a Programmable Chip
-Source follower
Also known as common drain amplifier.
+Vs
R3
Vin
Vin
Vout
R2
R3
R2
R1
0V
0V
0V
v gs  V in  V out
g m V in  V out  
V out V out

i
rd
R1
g m V in
i
 V out 

1  1 g
1  1 g
rd
R1 m
rd
R1 m
this is of the form Vout = no-load gain x Vin – output resistance x i
g m V in
if i = 0 then  V out 
1  1 g
rd
R1 m
1
the output resistance  R o 
1  1 g
rd
R1 m
so at node S
rd
gmVgs
S
R1
i
Vout
IPK06/05/17
-SPDT
Single Pole Double Throw
-SPI
System Packet Interface. SPI4.2 a standard that enables the
development of flexible, scalable systems for a converged data and telecommunications
infrastructure.
-SPST
Single Pole Single Throw
-SPT
Spanning Tree Protocol
-SQUID
Superconducting Quantum Interference Device
-SRAM
Static random Access Memory
-SS7
Signalling System no 7. The protocol used in every
telecommunications network in the world for the last 40 years.
-SSBW
Small Signal Bandwidth
-SSR
Solid State Relay
-STAR
Self Test And Repair
-STB
Set Top Box
-StMCP
Stacked Multi-Chip Package. Enables extra memory to be added
without increasing the footprint. – Mobile phones
-STN LCD
Super Twisted Nematic LCD
-Strataflash cell
memory cell technique in flash memory
-Super regenerative receiver
Developed by Armstrong in 1921. Greatly enhanced amplification is possible when a regenerative
detector is interrupted (quenched) at supersonic frequencies of the order of 20 to 100kHz. It is
preferable if the ratio of the signal frequency to the quenching frequency is of the order of 100 to
1000.
-SVPWM
-Swinging Choke
Space Vector Pulse Width Modulation
In rectifier circuits with conventional LC filters, the harmonic content
increases rapidly as the load decreases. The amplitude of harmonic content also decreases, but their
part of the rms current increases. The basis for the idea of a swinging choke device is a choke
whose inductance increases when the load decreases, ie its inductance changes according to the
current passing through it. To obtain a choke with a non-linear inductance, the form of the air gap is
changed. To increase the inductance at small currents, a 'step' is introduced in the middle of the
centre post in the EI-core choke.
IPK06/05/17
I Piece
Step
Centre Post
The air gap is small at low currents and grows as the current increases.
-Synchronous rectifiers.
Electronic switches, usually MOSFETs that are used to replace conventional diodes. This increases
switching rates and also reduces power consumption as a result of very low rds. On average the
power dissipation is reduced by at least a factor of two - often heat sinks are then not required
leading to a smaller profile.
TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
-TAB
-TAM
Tape Automated Bonding – used in SMT
Total Available Market
-TCM
Tar, Copy, Move
-TCU
Telematic Control Unit
-TDMA
Time Division Multiple Access. Used in mobile phones.
-TEC
ThermoElectric Cooler
-TELCO
Telephone company
-Telephone
Patented by Alexander Graham Bell in 1875.
-Telematics
A vehicle which has two-way communications, a location sensing
device and a control unit that is interfaced to the vehicle's electronic systems. Tend to fall into
vehicle-related and driver related categories.
-TEM
Tissue Equivalent Material.
-TEM
Telecomms Equipment Manufacturers
-TETRA
TErrestrial Trunked RAdio. The basis of the Airwave service used by
the emergency services in Great Britain.
IPK06/05/17
-THD
Total Harmonic Distortion.
As applied to power lines
THD  100 
 I 
sh 
 

h  2  I s1 
2
 100 
I s2  I s21
I s1
where Is is the total rms current, Is1 is the fundamental component and Ish is the harmonic
component of order h.
-Thermistor
Negative temperature coefficient. The resistance RT of a thermistor at
a temperature T K can be found by using the formula below, where RT1is the resistance at a given
temperature T1 K and B is the characteristic temperature for a given thermistor in K.
B
B 
R T  R T1 x e T  T1 
-Thermocouples
Type K
(Chromel (Ni-Cr alloy)/Alumel (Ni-Al alloy)). Low cost. Range -200°C to
+1200°C. Sensitivity is approximately 41V/C
Type J
(Iron/Constantan) Limited range -40C to +750C. Cannot be used above 760C as
an abrupt magnetic transformation causes permanent decalibration.
Type N
(Nicrosil (Ni-Cr-Si alloy)/Nisil (Ni-Si alloy)) High stability and resistance to high
temperature oxidation. Designed as an improvement to type K. Same temperature range as Type K
Type T
(Copper/Constantan) Popular in the food industry. Range -200C to 0C. The
positive conductor is made from copper.
-Thermoelectric coolers
Work on the Peltier effect. Can transfer heat at up to 125oC and have temp differences of up to
70oC. Temp should not normally exceed 85oC.
Discovered in 1821 by Thomas Seebeck (German physicist). Observed that if a closed circuit was
made from two dissimilar metals, an electric current flowed when the junctions were maintained at
different temperatures. The reverse of the process was demonstrated by French physicist Jean C.A.
Peltier in 1834. By inputting a current through the junctions of two different types of conductors, a
temperature differential can be maintained between the junctions. Heat, called the Peltier heat, is
either emitted or absorbed at the junction, depending on the direction of the current flow.
Misunderstood until 1838 when Heinrich Lenz used a bismuth and antimony junction to freeze a
drop of water.
Needs semiconductors with a good electrical conduction and poor heat conduction.
Bismuth Telluride is primarily used as the semiconductor material, heavily doped.
heat absorbed
negative
-TILS
positive
heat emitted
p-type semiconductor
ceramic insulators
n-type semiconductor
Technology Insertion into Legacy Systems. The insertion of a
computational layer into the test systems to emulate obsolete instrumentation
IPK06/05/17
-TIM
Thermal Interface Materials. Often greases and pads made from
silicone rubber. Also now using phase change materials, which are solid at room temperature but
become liquid at normal operating temperatures.
-TOF
Time Of Flight
-Toroidal Inductor
L
 N2 r 2
2R
where N is the number of turns,
R is the radius of the toroid,
r is the radius of the toroid cross section,
 is the permeability
AL
Inductance factor
The self-inductance that a coil of specified shape and dimensions placed on the core would have if it
consisted of one turn.
L
AL  2
N
-TPMS
Tyre Pressure Monitoring System. Now mandatory on new vehicles
in America.
-TPV
Thermal Photovoltaic Applications
-Transformer
Power and matching transformers wound so as to minimise the
capacitance between the windings and maximise the inductive coupling between the windings.
The formulae below assume 100% efficiency, i.e. Power out=Power in
Vs Ns Ip


Vp Np Is
2
 Np 


Z s  N s 
For power transformers, the primary should have sufficient inductance to ensure that the peak
currents are reasonable. Under no load conditions, for 230V mains, I01/Lp
Broadband matching transformer. The reactance of the primary winding should be >5 times the
impedance that the winding is designed to match. The core material should be chosen with
permeability to give this at the lowest frequency to be matched. As the frequency increases and the
permeability decreases - the match will then still work.
The transformer should be wound in the same manner as a power transformer, i.e. with one winding
placed over the previous one and insulated from it.
Zp
-Triac Controller
IPK06/05/17
load
L
100R
6k8
MT 2
1M
lin
10k
N
47nF
capacitors:
400V polypropylene
MT 1
g
BR100
10nF
100nF
-TSOP
Thin Small Outline Package
-TTCN
Software language used to write the test standards for 3G phones.
-Tuned Circuit
Combination of Inductance and Capacitance with resistance.
Series tuned.
V
L
C
R
By convention XL is taken as positive and XC is taken as negative.
Z
XL  XC2  R 2
At resonance XL = XC so Z = R where R is the equivalent total resistance of the circuit.
At resonance the voltage across the coil or capacitor is larger than that of the voltage generator.
This ratio of the voltage across the coil (or capacitor) to the supply voltage is called the Q of the
circuit.
At resonance, if a current of I is flowing, then V = I x R.
=> The voltage across the inductor VL = XL x I (true for C as well)
=> Q = VL/V = (XL x I)/(I x R) = XL/R
So at a given frequency, Q depends solely on L/R
Resonance is the frequency when XL=XC
1
f
2 π LC
Parallel tuned.
IPK06/05/17
L
C
V
r
Analysing the circuit in complex form gives: j XC j X L  r   j XC j X L  r 
Z

 j XC  j X L  r r  jX L  XC
Simplifying and separating into real and complex parts gives:2 j
r XC
X C r 2  X L X L  X C 
Z
2
r 2  X L  X C
At resonance, the imaginary part = 0
2
 r 2  X L XC  X L


1
r2

LC L 2
Assuming that r is much smaller than XL, then the resonance formula is very similar to that for the
series circuit.
1
ω
LC
ω
Assuming that r is much smaller than XL, then the impedance at resonance 
2
XC
X2
 L
r
r
-TV
Television. Invented by John Logie Baird in 1925
-TVSS
Transient Voltage Surge Suppression
UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU
-UCAV
Unmanned Combat Aircraft Vehicle
-UDM
Universal Data Model
-ULCH
Ultra Low-Cost Handsets
-UML
Unified Modelling Language
-UMTS
Universal Mobile Telephone Service
IPK06/05/17
-USB
Universal Serial bus
-USF
Uplink State Flag
-UVLO
Under Voltage Lock Out
-UWB
Ultra Waveband Technology
VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV
-VBR
Variable Bit Rate
-VCSEL
Vertical Cavity Surface Emitting Laser. Smaller and more efficient
than an edge emitting laser. Can also be tested on the wafer so cheaper to make.
-VDSL2
A proposed data standard for broadband. Can provide data rates of
between 30 and 100Mb/s over existing copper telecoms cables. VDSL1 offers the choice between
DMT (discrete multitone) and QAM (quadrature amplitude modulation), but VDSL2 focusses
solely on DMT and incorporates elements of ADSL2. VDSL2 is intended to provide symmetrical
100Mb/s data rates at distances between 200 and 500m and increases VDSL1's 12MHz spectrum to
30MHz. It is intended to be backwards compatible with ADSL and ADSL2.
LR (long reach) VDSL-enabled systems can support 1 - 4Mb/s over distances of 4 - 5 km, with
speed increasing as the length shortens. LR-VDSL2 uses frequencies down to 25kHz. The
upstream is similar to ADSL and the downstream band operates as an extended ADSL, reaching up
to 3.75MHz instead of 1.1MHz for ADSL and 2.2MHz as in ADSL2
-VDSM
Very Deep Sub-Micron
-Verilog
Language used to design and verify ICs
-VFD
Variable Frequency Drives.
-VFD
Vacuum Fluorescent Display.
-VHDL
Language used to design and verify ICs
-VHVIC
Very High Voltage Integrated Circuit
-VISC
Variable Instruction Set Communications.
-VLIW
Very Long Instruction Word
-VOA
Variable Optical Attenuators
-VOC
Volatile Organic Compounds
-VoIP
Voice over Internet Protocol
IPK06/05/17
-Voltage Doubler
+1.4V
+
V
0V
+
+
-1.4V
+2.8V
+
+
+1.4V
+
V
0V
+2.8V
+
+
+
+
+1.4V
+
V
0V
G3EUR
-VPS
Vapour Phase Soldering
-VRM
Voltage Regulator Module
IPK06/05/17
-VSAT
Very Small Aperture Terminal
-VSWR
Voltage Standing Wave Ratio. With VSWR unity, all power is
absorbed into the aerial. Higher VSWR values lead to reflection losses.
-VTCMOS
-VTM
Variable Threshold CMOS
Voltage Transformation Module.
-VXI
VWEbus eXtension Interface
WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW
-W-CDMA
Wide-Code Division Multiple Access. Used by many of the 3G
wireless standards. It involves spreading user signals, each with their own unique sequence, to
generate the waveform to be transmitted and despreading the received waveform to reconstruct the
original signal. Has to occur in real time and requires dedicated hardware. Advanced features such
as Multiple-User Detector/Interference cancellation systems (in which multiple users are tracked
and intra-cell interference removed) and space time adaptive systems (consisting of multiple
antennas to exploit spatial diversity) require very high throughput.
-WDL
Wavelength Dependent Loss
-WEEE
Waste Electrical and Electronic Equipment.
End 2004 - WEEE transposed into law.
First quarter 2005 - producers to register.
13th August 2005 - producers responsible for financing alongside retailer take-back.
1st July 2006 - RoHS ban becomes effective.
31st December 2006 – targets to be achieved for collection and recycling.
-Wheatstone bridge
Balance when
R1
R1 R 3

R2 R4
R1
R3
INPUT
R3
R2
R4
R2
INPUT
OUTPUT
R4
IPK06/05/17
-Wi-Fi
802.11b networking standard
-WLCSP
Wafer Level Chip Scale Package
-WNR
Weapons Neutron Research
-WORM
Write Once Read Many
-WWAN
Wireless Wide Area Network
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
-X Architecture
On chip architecture based on diagonal wiring, which reduces total
chip wire length by around 20%
-XIP
-XLPE
Execute In Place - NOR flash memory
Cross Linked Polythene - used in underground 400kV cables
-XMF
eXtendable Music Format. Extremely small approach to
encapsulation. Uses the Beatnik audio engine.
YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
-ZIF
Zero Insertion Force.
-ZCS
Zero Current Switching
-ZRAM
Zero Capacitor RAM
-ZVS
Zero Voltage Switching
www.maple4students.co.uk
free resources for students.
www.EducatorsCorner.com
Agilent training site