 generating {HEAD ~ a negative transition} in response to {TAIL ~ the signal} selected in sub step B 3 
generating { HEAD ~ a negative transition } in response to { TAIL ~ the signal } selected in sub step B 3
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH