With this variant, the input signal S1 is fed directly to the non linear network in {TAIL ~ front} of {HEAD ~ the amplifier} 4 
With this variant , the input signal S1 is fed directly to the non linear network in { TAIL ~ front } of { HEAD ~ the amplifier } 4
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH