| 摘要 |
PURPOSE:To obtain highly reliable reproduced data while improving peak-point detection precision and amplitude detection precision by putting AGC in normal operation and holding the amplitude of a reproduced signal invariably constant. CONSTITUTION:The reproduced signal read out by a reproducing head 101 has the DC component removed and only the AC component is amplified by a preamplifier 102. The amplitude variation of the amplified reproduced signal is constricted by an AGC amplifier 103. The output signal of the AGC amplifier 103 is supplied to a DC reproducing circuit 104 to add a DC component so that the potential of peak inspection corresponding to a bit is constant. An AGC feedback circuit 108 controls the AGC amplifier 103 so that the output signal amplitude of a DC reproducing circuit 104 is constant. An amplitude detecting circuit 109, on the other hand, detects the reproduced signal after the DC component is added by the DC reproducing circuit 104 having an amplitude larger than a specific level. Consequently, data reproduction of high quality having neither a drop-in nor a drop-out is performed. |
