PURPOSE: To obtain an accurate data signal without reference to the wow and flutter of a recording and reproducing device by putting a data signal and clock pulses together and recording them on a signal track, and then separating its reproduced signal into a reproduced data signal and reproduced clock pulses.

CONSTITUTION: The clock pulses (a) and data signal (b) are ANDed by an AND gate circuit G, whose output (c) is supplied to an adder AD, the output (d) of which is passed through a low-pass filter LPF to obtain an output (f) from which higher harmonic components are removed. Consequently, a modulator MOD imposes frequency modulation on a carrier fc of audio frequency to obtain a recording signal SR with a narrow frequency band, thereby allowing the recording and reproducing device to perform recording to a single track freely. After the recording signal SR is recorded by the recording and reproducing device, its reproduced signal SP is separated into the clock pulses and the reproduced data signal is sampled.