Define the bandwidth of a frequency modulated signal?

In a frequency modulated (FM) signal the information is encoded through varying the frequency of a carrier wave in accordance with the modulating signal. Consequently the bandwidth of an FM signal is a function of the maximum frequency deviation from the carrier frequency (which is related to the amplitude of the modulating signal) as well as the highest modulating frequency that needs to be transmitted.

The Carson's bandwidth rule provides an estimate for the bandwidth required to transmit an FM signal, and is given by:

$$B_T=2(\Delta f+f_{max})$$

where:

- \(B_T\) is the bandwidth of the FM signal

- \(\Delta f\) is the maximum frequency deviation

- \(f_{max}\) is the highest modulating frequency

Carson's bandwidth rule is generally valid for narrowband FM signals, where \(\Delta f\) < \(f_{c}\) (the carrier frequency). In the case of wideband FM signals, the actual bandwidth may be wider than the one predicted by Carson's rule.