A system and method to optimize the quality of a modulated signal. In one aspect, an AM demodulator is used in conjunction with proper bandwidth selection of an FM signal. For example, the AM demodulator can be used to generate an instantaneous absolute value of the FM signal. The average value of the FM signal over a period of time is subtracted from the instantaneous absolute value in order to determine a variance in amplitude in the FM signal. In another aspect, several filters may be tested and the one having the lowest variance in amplitude may be used in order to select the filter having the desirable bandwidth.