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9-6: Typical Receiver Circuits
A squelch circuit, or muting circuit, is found in most communications receivers.
The squelch is used to keep the receiver audio turned off until an RF signal appears at the receiver input.
In AM systems such as CB radios, the noise level is high and can be very annoying.
Squelch circuits provide a means of keeping the audio amplifier turned off during the time that noise is received in the background and enabling it when an RF signal appears at the input.