Reference delay unit 205 generates a reference signal by delaying {HEAD ~ its input signal} by {TAIL ~ an x unit time period}, where x is an integer 
by
Reference delay unit 205 generates a reference signal by delaying { HEAD ~ its input signal } by { TAIL ~ an x unit time period } , where x is an integer
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH