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