# Definition of Frequency modulation & Frequency deviation in FM

## In Frequency Modulation -

Options:

a) Amplitude of the carrier remains same
b) Frequency of the carrier varies in accordance with the modulating signal
c) The number of side bands are infinite
d) All of the above

Correct Answer: d) All of the above

Explanation:

In Frequency Modulation amplitude of the carrier remains same where as frequency of the carrier varies in accordance with the modulating signal. The variation of the instantaneous carrier frequency is proportional to the modulating signal. The number of side bands are infinite in FM signal.

## Frequency deviation in FM is

Options:

a) Change in carrier frequency to the frequency above and below the centre frequency.
b) Formation of side bands
c) The variation of the instantaneous carrier frequency in proportion to the modulating signal
d) All of the above

Correct Answer: d) All of the above

Explanation:

In Frequency Modulation, frequency of the carrier varies in accordance with the modulating signal. The variation of the instantaneous carrier frequency is proportional to the modulating signal. A number of side bands are formed. There is deviation of carrier frequency above and below the carrier frequency. This is known as frequency deviation.