Abstract: A digital signal recording/reproducing system specifically has an adaptive automatic equalizer for performing automatic waveform equalization disposed in a reproducing circuit of an RF system. In order to provide a run-up pattern which enables stable operation settlement of the adaptive automatic equalizer and a clock reproducing PLL at the time of reproduction, the digital signal recording/reproducing system comprises a run-up code generator for producing a run-up pattern composed of a combination of at least two digital value series of different inversion intervals. Thus, since an optimum run-up pattern for the reproducing circuit of the RF system is produced and recorded on a recording medium within a fixed period at the time recording, stable settlement of the operation of the clock reproducing PLL and the adaptive automatic equalizer is attained within a run-up period at the time of reproduction, thereby making it possible to suppress occurrence of a code error to a minimum.

Abstract: A digital modulation method for modulating 8-bit digital data into 14-bit digital modulation codes. The number of consecutive identical bits in a series of 14-bit digital modulation codes is restricted to 2-7. The absolute value of DSV at the end of each 14-bit digital modulation code is restricted to 2 or less, and the absolute value of DSV at each bit of any 14-bit digital modulation codes is limited to 7 or less. The direct current component of the 14-bit modulation codes can be effectively reduced.

Abstract: A method for magnetic recording and reproduction comprising the steps of: (1) magnetically multiple-recording signals on a magnetic recording medium comprising a support having thereon an upper magnetic recording layer comprising barium ferrite having an increased coercive force at 60.degree. C. or more and a lower magnetic recording layer comprising at least one of chromium dioxide and Co-modified iron oxide, having a decreased coercive force at 60.degree. C. or more, disposed between said upper magnetic recording layer and said support; (2) heating said magnetic recording layers prior to reproduction due to a reproducing head; and (3) reproducing said magnetically recorded signal from said heated magnetic recording medium which is multiple-recorded.