Two operational amplifiers 68 and 70 form {HEAD ~ part} of {TAIL ~ circuit} 50 with inverting terminal 72 of op amp 68 common with anode 54 of photodiode 52 
of
Two operational amplifiers 68 and 70 form { HEAD ~ part } of { TAIL ~ circuit } 50 with inverting terminal 72 of op amp 68 common with anode 54 of photodiode 52
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH