Introduction to FM
The general sinusoidal modulated FM signal
is defined by:
_{ }
Modulation Index
The FM modulation index is defined as the ratio of carrier
deviation to modulation frequency:
_{ }
As a result, the FM equation is generally written as:
_{ }
FM generates an infinite number of side frequencies each
of which is an integer multiple of the modulation signal frequency.
Bessel’s functions are used to calculate their amplitude.
A plot of the amplitudes of the carrier and first five
side frequencies as a function of modulation index resembles:
