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 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 Noise occurs in digital and analog systems, and can affect files and communications of all types, including text, programs, images, audio, and telemetry.

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 THERMAL TRANSIENT TIME ATHMOSPHERIC IMPULSE MAN-MADE INTERFERENCE

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 analog-to-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 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.