{HEAD ~ The peaks} of {TAIL ~ the forward and rear output pulses} are converted into DC voltage levels, which are then fed into a comparator circuit 
of
{ HEAD ~ The peaks } of { TAIL ~ the forward and rear output pulses } are converted into DC voltage levels , which are then fed into a comparator circuit
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH