If {HEAD ~ the periodic pulse} is not detected by {TAIL ~ the slave processor}, the slave processor disables the output of the master processor wherein the output of the slave processor becomes enabled 
is not detected by
If { HEAD ~ the periodic pulse } is not detected by { TAIL ~ the slave processor } , the slave processor disables the output of the master processor wherein the output of the slave processor becomes enabled
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH