a tenth step which multiplies {TAIL ~ the first time ratio} with {HEAD ~ the phase proceeding amount} of the speed detection signal and computes the phase proceeding amount of the first speed detection signal after the current reproducing control signal is inputted; and 
a tenth step which multiplies { TAIL ~ the first time ratio } with { HEAD ~ the phase proceeding amount } of the speed detection signal and computes the phase proceeding amount of the first speed detection signal after the current reproducing control signal is inputted ; and
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD 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