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squelch

Squelch suppresses noise signals that interfere with communication or speech signals. This can be during the playback of records and compact discs, in radiotelephony, in hearing aids or during the reception of unmodulated carrier signals during transmission pauses.

Squelchers are electronic circuits that suppress audio or video signals when they are strongly affected by noise or no longer stand out against the noise. This is the case, for example, when an unmodulated carrier signal is received. The automatic gain control( AGC) will up-regulate the gain of the AF and RF amplifiers and thus disproportionately amplify the noise. In such a case, the squelch function takes effect and blocks the noise. Only when the carrier signal is modulated again, the noise or carrier signal blocking is removed.

In some equipment concepts, the squelch is preset as a default value, in others the squelch is adjustable. This is often the case with voice radios.

Informations:
Englisch: squelch
Updated at: 23.02.2011
#Words: 152
Links: noise (N), communication (COM), speech, carrier, transmission
Translations: DE
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