DIGITAL SIGNAL RECORDING AND REPRODUCING SYSTEM

PURPOSE:To prevent unrequired data from being recorded and to detect tracking information with high precision by applying DC free modulation on data to be recorded generally, disturbing the DC free modulation at a certain point on a track, and setting disturbance differently between adjacent tracks. CONSTITUTION:A magnetic head 6 modulates a data string 17 to be recorded in track length by a modulator 4, however, a modulation rule in modulated output 17 is disturbed in periods (19-27). The DSV (Digital Sum Variation) of each block of the modulated output 18 goes to '0' in the periods (19-27), and the modulation rule is disturbed, then, it changes like DSV28, and in the DSV28 and 29, the disturbance of the modulation rule are set differently between the adjacent tracks. At the time of reproduction, a signal is introduced to a demodulator 9 and a filter 14, and the modulator 4 performs a DC free operation almost in all periods, and the DSV changes in extremely limited period. Therefore, different signals between the adjacent tracks can be obtained from the filters 14. In such a way, it is possible to detect a tracking error correctly as holding a recording and reproducing function.