A squelch detection technique that monitors noise at the FM demodulator output, at frequencies above the audio range. A high level of noise in this region indicates a weak or unusable RF signal, or some form of interference.
(See Squelch)

Receiver squelch (muting) that is based on RF signal strength present at the receiver input. When the RF signal is considered high enough to output audio of acceptable quality, the receiver is un-muted.
(See Squelch)

A receiver circuit designed to mute the audio output when the received signal is too weak to provide acceptable audio or, in some cases, when the wrong signal is being received.
(See Noise Squelch, Signal Level Squelch, Tone Coded Squelch)

Tone Coded Squelch is a way of letting a receiver know that a correct signal is being received. The tone sent is at a frequency outside human hearing and is usually combined with another type of muting, such as signal level squelch.
(See Squelch)