{TAIL ~ The emitter follower pair} is operative to receive {HEAD ~ an input differential voltage signal} for shifting the input differential voltage signal to develop a shifted differential voltage signal 
{ TAIL ~ The emitter follower pair } is operative to receive { HEAD ~ an input differential voltage signal } for shifting the input differential voltage signal to develop a shifted differential voltage signal
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH