This intermittent signal {HEAD ~ 8 a} is referred to as {TAIL ~ intermittent input signal} 8 a 
This intermittent signal { HEAD ~ 8 a } is referred to as { TAIL ~ intermittent input signal } 8 a
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH