Abstract: In an information recording medium from which information recorded on each pit is reproduced by an optical detection system that obtains a reproduced signal corresponding to each pit by scanning the information recording medium along pit rows by a light beam, data of high recording density can be accurately reproduced by a simple arrangement by shifting in a step-wise fashion edge positions of an information pit from a predetermined reference position in response to digital information to be recorded within a range corresponding to a predetermined shift period smaller than a transition period of a reproduced signal determined in response to a transfer characteristic of the optical detection system. Therefore, a nonlinear intersymbol interference can be reduced without emphasizing a noise component.

Abstract: In an information recording medium from which information recorded on each pit is reproduced by an optical detection system that obtains a reproduced signal corresponding to each pit by scanning the information recording medium along pit rows by a light beam, data of high recording density can be accurately reproduced by a simple arrangement by shifting in a step-wise fashion edge positions of an information pit from a predetermined reference position in response to digital information to be recorded within a range corresponding to a predetermined shift period smaller than a transition period of a reproduced signal determined in response to a transfer characteristic of the optical detection system. Therefore, a nonlinear intersymbol interference can be reduced without emphasizing a noise component.

Abstract: Magneto-optically recorded data can be recorded at high density, such that the data can be overwritten by a simple arrangement and with a small energy. Also, data of high recording density can be accurately recorded and reproduced by a simple arrangement. An alternating field having the same frequency as that of a recording fundamental clock generated by a PLL circuit (8) is generated by a coil (5) that is part of a tank circuit (7) and then applied to a magneto-optical disc (1). A phase of the recording fundamental clock is modulated by a phase modulating circuit (12) in association with recording data and a pulse synchronized with leading edge and trailing edge of such clock is generated by a pulse generating circuit (13). An optical pickup device (4) irradiates the magneto-optical disc (1) with a laser light in synchronism with the pulse.