When a high level or a positive signal is applied to the AND gate 33 from the comparator 21, {HEAD ~ the clock pulses} are supplied to {TAIL ~ the digital counter} 34 and are counted up thereat 
When a high level or a positive signal is applied to the AND gate 33 from the comparator 21 , { HEAD ~ the clock pulses } are supplied to { TAIL ~ the digital counter } 34 and are counted up thereat
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH