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GROUP MEMBERS
0F GROUP 7
Mr.Syed Ahmad Sobrie B Syed Ramli (Leader)
Ms.Noor Ropidah Bt Bujal (Secretary)
Ms.Tuan Nor Balkhis Bt Tuan Harun
Mr.Rajes Kanna A/L Seluwmuthu
Mr.Mohd Aizuddin B Abdullah
Mr.Mohd Shariman B A.Aziz
NOISE
INTRODUCTION


Noise is unwanted
electrical or
electromagnetic
energy that degrades
the quality of signals
and data.
Noise occurs in digital
and analog systems,
and can affect files
and communications of
all types, including
text, programs,
images, audio, and
telemetry.

Noise can be divided into
2 general categories
a. Correlated noise
implies relationship
between the signal and
the noise, exist only
when signal is present
b. Uncorrelated noise
present at all time,
whether there is signal or
not.
i) Internal noise
ii) External noise
UNCOLERATED NOISE
External noise
∑
Generated outside the
device or circuit
a. Atmospheric
b. Extraterrestrial
c. Man made
Internal noise
∑
Generated within a
device or circuit.
a. Shot noise
b. Transit-time noise
c. Thermal noise
CORRELATED
FACTS
UNCORRELATED
CORRELATED
HARMONIC
DISTORTION {HT}
INTERMODULATION
DISTORTION {ID}
UNCORRELATED
EXTERNAL
INTERNAL
SHOT
ATHMOSPHERIC
IMPULSE
MAN-MADE
INTERFERENCE
THERMAL
TRANSIENT
TIME
NOISE
REDUCTION
TECHNIQUES
Techniques on How To
Eliminated or Reduces
Noise
Signal Filtering

often used in eddy current testing to eliminate
unwanted frequencies from the receiver signal.

while the correct filter settings can significantly
improve the visibility of a defect signal, incorrect
settings can distort the signal presentation and
even eliminate the defect signal completely.

filtering is applied to the received signal and,
therefore, is not directly related to the probe
drive frequency.
Filters Effects
 The HPF allows high frequencies to pass and filters out
the low frequencies.
 The LPF allows low frequency to pass and filters out the
high frequency.
 First filtered out with a HPF and then high frequency
electronic noise was filtered with a LPF to leave a
clearly visible flaw indication.
 It should also be noted that since flaw indication signals
are comprised of multiple frequencies, both filters have
a tendency to reduce the indication signal strength.
 Additionally, scan speed must be controlled when using
filters.
 Scan over a flaw too slow and the HPF might filter out
the flaw indication. Scan over the flaw too fast and the
LPF might eliminate the flaw indication.
Digital Signal Processing



Refers to various

techniques for improving
the accuracy and reliability
of digital communications.
Basically, DSP works by
clarifying, or
standardizing, the levels or
states of a digital signal. 
A DSP circuit is able to
differentiate between
human-made signals, which
are orderly, and noise,
which is inherently chaotic.
If an incoming signal is
analog, for example a
standard television
broadcast station, the
signal is first converted to
digital form by an analogto-digital converter (ADC).
The DSP circuit adjusts
the levels of the resulting
digital signal so they are at
the correct values.
Burst Noise Eliminating Equipment
We arranged a burst
noise eliminating
equipment and
characterized the
1/f and burst noises
In some electronic
materials,components
the electric contacts
and bipolar
transistors
Analog Signal Transmission
(Noise and Grounding)

A ground is a conducting
flow path for current
between an electric circuit
and the earth. Ground wires
are typically made with
materials that have very low
resistance. Ground wires
also safeguard against
unwanted common-mode
signals and prevent
accidental contact with
dangerous voltages. Return
lines carry power or signal
currents.

The second ground is for the signal ground. This
ground is necessary to provide a solid reference for
the measurement of all low-level signals. It is very
important that this ground is grounded separate and
isolated from the system ground. In a single-point
ground configuration, minimal current can flow in the
ground reference.
LEARNING ISSUES



Noises are every
where.
Noise can’t be
eliminated but can be
reduced.
Noise comes from many
sources that related to
communications
transmission.


Certain techniques
of reducing noise
can be used by
certain noise.
The longer the
length of
transmission the
higher the noises
are.
CONCLUSION
Noise is unwanted electrical or electromagnetic
energy that occurs during data and signals
transmission. It can not be eliminated but can
be reduce with several reduction techniques for
several noise.