At 4/18/2007 11:16, you wrote: > > The Micor Chip squelch is a well known circuit with action/operation > > probably based on voice band energy/information and its detection > > against other information (or lack there off) and/or noise. > >The M6709 is basicly 2 op-amps, AC to DC rectifier, a window >comparator and a audio switch. R/C filters external to the chip work
Somehow, I feel there's a bit more to it than just the above, for it performs so well. >with the op-amps to create band pass filtering that passes high >frequency noise which is then rectified and compared to set levels at >which point it is deterimned whether there should be a fast squelch >closure (5 to 15mS) or a slow (about 150mS) one. Actually, if implemented & installed properly the fast squelch is faster (2-3 ms), resulting in virtually complete squelch tail elimination. I find the slow squelch to be around 300-400 ms. Bob NO6B
