METHOD AND APPARATUS FOR DETECTING FLAW OF RECORDING MEDIUM

摘要

PURPOSE:To make it possible to efficiently detect the minute flaw on a recording medium, by detecting the phase shift between the peak amplitude width and peak point of a playback amplitude signal playbacked from the recording medium. CONSTITUTION:A mechanism system is constituted so that a magnetic disc 101 is rotatably driven by a motor 111 and the recording playback of information is performed by a magnetic head 102. A recording circuit system is constituted so that the writing data outputted from a control circuit 110 is modulated by a data converting circuit 104 and amplified by a writing amplifier 103 to perform the recording of information to a disk 101. A playback system is constituted so that a read playback signal is amplified by a reading amplifier 105 and the peak point position of the amplitude of the playback signal is detected by a peak detection circuit 106 and the lowering in amplitude at an arbitrary position is detected by a level detection circuit 107. The outputs of the circuits 106, 107 are inputted to a data forming circuit 108 and the signal of which the amplitude is lowered to an arbitrary level or less forms no data even if the peak point has been detected and only a signal reaching predetermined amplitude is demodulated to data. The output of the circuit 108 is inputted to a data discriminating circuit 109 to detect a flaw.