second differential amplifier means for generating an up down differential output signal which is a function of {TAIL ~ the difference} in {HEAD ~ amplitude} of said up and down output pulses; and 
second differential amplifier means for generating an up down differential output signal which is a function of { TAIL ~ the difference } in { HEAD ~ amplitude } of said up and down output pulses ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH