wherein in step , after {TAIL ~ a predetermined number} of {HEAD ~ pulses} have been counted by step , the pulse is made to fall synchronously with the remaining one of the first clock signal and the clock signal generated in step  
wherein in step , after { TAIL ~ a predetermined number } of { HEAD ~ pulses } have been counted by step , the pulse is made to fall synchronously with the remaining one of the first clock signal and the clock signal generated in step
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH