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