FM results when the time derivative of the phase of the carrier is varied linearly with the message signal m(t). The frequency deviation is proportional to the derivative of the phase deviation. Thus, the instantaneous frequency of the output of the FM modulator is maximum when the message signal m(t) is maximum and minimum when m(t) is minimum.
Carson’s Rule is used to determine the bandwidth of the FM wave. According to Carson’s Rule, the bandwidth is given by:...