The voltage comparator produces {TAIL ~ a first signal} when the detected signal is below the squelch level and produces a second signal when {HEAD ~ the detected signal} is above the squelch level 
The voltage comparator produces { TAIL ~ a first signal } when the detected signal is below the squelch level and produces a second signal when { HEAD ~ the detected signal } is above the squelch level
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH