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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. IPK06/05/17 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 IPK06/05/17 144.0 – 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 st A1 mt cos2 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 mt B cos2 f m t with B > 0, equation 1 becomes eq3 st A cos2 f c t 0.5A cos2f c f mt 0.5A cos2f c f mt 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 Sf 0.5Af f c f f c 0.5AMf f c Mf 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, IPK06/05/17 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 st Amt cos2 f c t Similar to equation 3, a DSB-SC for a single tone modulation is represented as eq6 st 0.5A cos2f c f mt 0.5A cos2f c f mt If a four-quadrant multiplier is used to generate the product of A(1+m(t)) and the carrier waveform cos(2fct) 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 IPK06/05/17 -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. IPK06/05/17 -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. IPK06/05/17 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. IPK06/05/17 -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. IPK06/05/17 +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. IPK06/05/17 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 IPK06/05/17 -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. IPK06/05/17 green current red current blue current n lightly doped drain 0.2 m blue photon collection p-well n-well 0.6m green photon collection 2m 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. IPK06/05/17 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 IPK06/05/17 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 = KTI 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 IPK06/05/17 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 = kN 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 1bar. An electret microphone does not need a polarizing voltage or current. However it does require a small feed current of between 50A 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 1000C to 1400C, 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/kgC Thermal conductivity 1-5W/mC 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 4R 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 4r2 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 L9r 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:0.4T VLF E:614V/m E:4V/m 3-30kHz B:83T B:0.1T 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 (155C), Class B (130C) 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 et dt TD d et CO( t ) Pe( 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 10mproduces 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 2C0 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 41V/C Type J (Iron/Constantan) Limited range -40C to +750C. Cannot be used above 760C 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 -200C to 0C. 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, I01/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 XC2 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 jX 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