Question

The amount of frequency deviation in FM signal depends on

• A. Amplitude of the modulating signal
• B. Carrier frequency
• C. Modulating frequency
• D. Transmitter amplifier

Hint:

Frequency Modulation (FM). Carrier frequency is varied. Amount of Frequency Deviation (\(\Delta f\)) \(\propto\) Amplitude of modulating signal. Rate of Frequency Deviation \(\propto\) Frequency of modulating signal.

Answer 1

The Correct Option is A

In Frequency Modulation (FM), the instantaneous frequency of the carrier signal is varied in proportion to the instantaneous amplitude of the modulating signal (e
g
, audio signal)
The amount by which the carrier frequency deviates from its unmodulated value (the center frequency) is called the frequency deviation (\(\Delta f\))
This deviation is directly proportional to the amplitude of the modulating signal
A louder audio signal (higher amplitude) causes a larger frequency deviation
The *rate* at which the frequency changes depends on the *frequency* of the modulating signal, but the *amount* of deviation depends on the modulating signal's *amplitude*
The carrier frequency is the center frequency being modulated
The transmitter amplifier affects the signal power, not the frequency deviation directly