Question

Pre-emphasis and De-emphasis are used in ________.

• A. Frequency Modulation
• B. Amplitude Modulation
• C. Pulse Amplitude Modulation
• D. Phase Modulation

Hint:

Pre-emphasis and de-emphasis are \textbf{noise-reduction techniques} used in \textbf{Frequency Modulation (FM)}. Remember: \textbf{FM = Emphasis techniques}.

Answer 1

The Correct Option is A

Step 1: Understanding the Terms
Pre-emphasis: Boosts the amplitude of high-frequency signals before transmission.
De-emphasis: Attenuates the high frequencies at the receiver.
Step 2: Why it is Used in FM
In FM transmission, high-frequency signals tend to get corrupted by noise. Pre-emphasis boosts these components to combat the effect of noise.
At the receiver, de-emphasis returns the signal to its original state, improving signal-to-noise ratio.
Step 3: Why Not Others?
AM and PM do not suffer from this kind of high-frequency noise distortion, so emphasis techniques are not commonly applied.