A digital signal regeneration method for demodulating data despite a fluctuation in reading rate or variation in regeneration pulse duration due to abnormalities in a recording medium from which data is read, the digital signal consisting of output pulses produced by binary coding an analog signal which is acquired by reading information from the recording medium, comprising the steps of:
- extracting a pulse spacing of a binary-coded regeneration output pulse;
- detecting a multiple indicating the number of times the extracted pulse spacing is larger than a predetermined reference cycle;
- calculating a new reference cycle using the extracted pulse spacings and the detected multiples of a plurality of predetermined sequential regeneration output pulses;
- generating a demodulating clock having the new reference cycle;
- synchronizing the demodulation clock in phase with regeneration output pulses in given durations, and synchronizing the demodulating clock in phase with a regeneration output pulse coming in a given initial range of data regenerated not by locking the demodulating clock in a given duration but by matching the demodulating clock and the regeneration output pulse coming in said initial range;
- and
- demodulating a binary-coded regeneration output pulse train using the demodulating clock.