{HEAD ~ A reference delay unit} delays the first delayed signal by a predetermined reference time period to generate {TAIL ~ a reference signal} 
{ HEAD ~ A reference delay unit } delays the first delayed signal by a predetermined reference time period to generate { TAIL ~ a reference signal }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL