PHYSICAL LAYER AND TRANSMISSION MEDIA
ANALOG TRANSMISSION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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As they boost signal to noise ratio
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They keep constant SNR
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Noise reduction
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Signal reduction
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Detailed explanation-1: -Answer: Pre-emphasis works by boosting the high-frequency portion of the signal. This compensates for the high-frequency loss in the cable. De-emphasis works by cutting the low-frequency portion of the signal. This may be coupled with an increased transmit voltage.
Detailed explanation-2: -De-emphasis means attenuating those frequencies by the amount by which they are boosted. However pre-emphasis is done at the transmitter and the de-emphasis is done in the receiver. The purpose is to improve the signal-to-noise ratio for FM reception.
Detailed explanation-3: -Pre-emphasis circuit is a high pass filter or differentiator which allows high frequencies to pass, whereas de-emphasis circuit is a low pass filter or integrator which allows only low frequencies to pass.