The method,1, wherein {HEAD ~ said difference count} and said pulse count are stored separately on the occurrence of {TAIL ~ a pulse} of said second series in first and second storage means, respectively 
The method,1 , wherein { HEAD ~ said difference count } and said pulse count are stored separately on the occurrence of { TAIL ~ a pulse } of said second series in first and second storage means , respectively
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH