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Transmission impairement (1)

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Daffodil international University
Daffodil international University

This document discusses transmission impairment, which refers to degradation of signals as they travel through transmission media. There are three main causes of transmission impairment: 1) attenuation, which is the loss of signal energy as it passes through a medium, 2) distortion, which is a change in the signal's form or shape, such as different frequency components arriving at different times, and 3) noise, which adds unwanted signals from sources like thermal effects, interference, or crosstalk between wires. Attenuation is measured in decibels and can be compensated for using amplifiers, while signal to noise ratio (SNR) measures the quality of a transmission system by comparing the signal strength to the noise power.

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TRANSMISSION IMPAIREMENT
Presented by: Mahir Shahriar Alam 152-15- 5619 Md. Fardin Hassan 152-15-5532 Talha Zubaer 152-15-5705
TRANSMISSION IMPAIRMENT Signals travel through transmission media, which are not perfect. The imperfection causes signal impairment. This means that the signal at the beginning of the medium is not the same as the signal at the end of the medium. What is sent is not what is received. Three causes of impairment are 1. Attenuation 2. Distortion 3. Noise
ATTENUATION Means loss of energy => weaker signal When a signal travels through a medium it loses energy overcoming the resistance of the medium Amplifiers are used to compensate for this loss of energy by amplifying the signal.
MEASUREMENT OF ATTENUATION To show the loss or gain of energy the unit decibel is used. dB = 10log10P2/P1 P1 = input signal P2 = output signal
DISTORTION Means that the signal changes its form or shape Distortion occurs in composite signals Each frequency component has its own propagation speed traveling through a medium. The different components therefore arrive with different delays at the receiver. That means that the signals have different phases at the receiver than they did at the source.
Distortion
NOISE There are different types of noise Thermal - random noise of electrons in the wire creates an extra signal Induced - from motors and appliances, devices act are transmitter antenna and medium as receiving antenna. Crosstalk - same as above but between two wires. Impulse - Spikes that result from power lines, lightning, etc.
Noise
SIGNAL TO NOISE RATIO (SNR) To measure the quality of a system the SNR is often used. It indicates the strength of the signal wrt the noise power in the system. It is the ratio between two powers. It is usually given in dB and referred to as SNRdB.
Two cases of SNR: a high SNR and a low SNR
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Transmission impairement (1)

  • 2. Presented by: Mahir Shahriar Alam 152-15- 5619 Md. Fardin Hassan 152-15-5532 Talha Zubaer 152-15-5705
  • 3. TRANSMISSION IMPAIRMENT Signals travel through transmission media, which are not perfect. The imperfection causes signal impairment. This means that the signal at the beginning of the medium is not the same as the signal at the end of the medium. What is sent is not what is received. Three causes of impairment are 1. Attenuation 2. Distortion 3. Noise
  • 4. ATTENUATION Means loss of energy => weaker signal When a signal travels through a medium it loses energy overcoming the resistance of the medium Amplifiers are used to compensate for this loss of energy by amplifying the signal.
  • 5. MEASUREMENT OF ATTENUATION To show the loss or gain of energy the unit decibel is used. dB = 10log10P2/P1 P1 = input signal P2 = output signal
  • 6. DISTORTION Means that the signal changes its form or shape Distortion occurs in composite signals Each frequency component has its own propagation speed traveling through a medium. The different components therefore arrive with different delays at the receiver. That means that the signals have different phases at the receiver than they did at the source.
  • 8. NOISE There are different types of noise Thermal - random noise of electrons in the wire creates an extra signal Induced - from motors and appliances, devices act are transmitter antenna and medium as receiving antenna. Crosstalk - same as above but between two wires. Impulse - Spikes that result from power lines, lightning, etc.
  • 10. SIGNAL TO NOISE RATIO (SNR) To measure the quality of a system the SNR is often used. It indicates the strength of the signal wrt the noise power in the system. It is the ratio between two powers. It is usually given in dB and referred to as SNRdB.
  • 11. Two cases of SNR: a high SNR and a low SNR