In another circuit one of either the anodes or cathodes of each diode is common and the other is {HEAD ~ input} into {TAIL ~ the inverting terminal} of a separate operational amplifier 
into
In another circuit one of either the anodes or cathodes of each diode is common and the other is { HEAD ~ input } into { TAIL ~ the inverting terminal } of a separate operational amplifier
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH