squelch(redirected from PL tone)
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Electronics a circuit that cuts off the audio-frequency amplifier of a radio receiver in the absence of an input signal, in order to suppress background noise
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
To automatically quiet a receiver by reducing its gain in response to a specified characteristic of the input.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved