Since the pulse g3 is inputted, {HEAD ~ the control circuit} 20 does not produce {TAIL ~ any pulse} 
not produce
Since the pulse g3 is inputted , { HEAD ~ the control circuit } 20 does not produce { TAIL ~ any pulse }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL