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