查了一下原理
Voice squelch control function This function is useful when you don't want unmodu- lated signals. When the voice squelch control function is activated, the receiver checks received signals for voice components. If a receiver signal includes voice components, and the tone of the voice components changes within 1 sec., squelch opens. If the received signal includes no voice components or the tone of the voice components does not change within 1 sec., squelch closes. ➥ While is selected with [MENU], push [F5 to switch the VSC (Voice Squelch Control) function ON and OFF. • "VSC" appears when the function is activated. • The VSC function activates for phone modes (SSB, AM and FM). • The VSC function can also be used for scanning operation in AM or FM mode (p. 70)
http://www.manualslib.com/manual/281866/Icom-Ic-746pro.html?page=67
[ 此帖被BG2BHC在2013-12-27 21:56重新编辑 ]
