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