Frequency Modulation (FM)

Frequency modulation (FM) is a type of angle modulation in which the frequency of a sinusoidal carrier wave deviates from a center frequency by an amount proportional to the instantaneous value of the message signal. In FM, the center frequency is the carrier frequency.

Frequency modulation can be expressed using the general equation for angle modulation.

where

A_c is the carrier amplitude
f_c is the carrier frequency
k_f is the frequency deviation constant in Hz/V
f_m is the frequency of the message signal

Refer to the NI Developer Zone at ni.com/zone for more information about frequency modulation.