Simple suppression [suppressing amplitude modulation]

In radio-frequency (RF) systems based on angle-modulated signaling, e.g., phase-shift keying (PSK) or analog frequency modulation (FM), amplitude variations due to the non-ideality of filter elements, channel noise, and signal fading can result in degradation of the system noise performance and produce nonlinear distortions. In order to reduce noise effects and increase the interference immunity, it is essential to remove the amplitude variations prior to detection. Traditionally, a ratio detector has been used in FM receivers for eliminating amplitude modulation (AM). This paper reports a method for suppressing amplitude modulation using simple circuit.