AM Noise ArticleA simple definition of AM noise is: unwanted amplitude modulation of an FM carrier. There are two types of AM Noise, synchronous and asynchronous. Asynchronous noise consists of amplitude modulation unrelated to the FM modulation of the carrier, typically caused by power supply hum or vibration. Unless there is a serious problem with the transmitter, asynchronous AM is far less significant than synchronous AM. Unwanted AM modulation produced by normal FM carrier modulation from baseband audio and all subcarriers is synchronous AM, sometimes referred to as incidental AM. Consistent control of synchronous AM noise can result in improved audio clarity, better stereo separation, lower crosstalk into subcarriers and extended service area.
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