In FM transmitter the rate of frequency swing is determined by the?

In FM transmission, the rate of frequency swing is determined by the modulation index. The modulation index is the ratio of the frequency deviation to the modulating frequency. The higher the modulation index, the greater the frequency swing.

The modulation index is given by the following equation:

$$m = \frac{\Delta f}{f_m}$$

where:

* m is the modulation index

* Δf is the frequency deviation

* fm is the modulating frequency