A squelch detecting circuit comprises {HEAD ~ a narrow bandpass filter} for obtaining, as a filtered signal, {TAIL ~ a desired IF carrier frequency signal} 
for obtaining
A squelch detecting circuit comprises { HEAD ~ a narrow bandpass filter } for obtaining , as a filtered signal , { TAIL ~ a desired IF carrier frequency signal }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL