| 摘要 |
PURPOSE:To eliminate a reading error due to a small defect on a medium by removing pulses of certain pulse width or less after shaping a readout waveform into a rectangular wave by a limiter. CONSTITUTION:To remove narrow pulses due to a medium defect from the output signal of limiter 5, a kind of LPF composed of pulse eliminator 6, capacitor C and resistance RT is provided and for the compensation of signal delay by capacitor C, the delay circuit is added between level slicer 8 and data discriminating circuit 10. For narrow pulses such as pulses P3 and P3', the time constant determined by resistance RT and capacitor C is determined so that output signal O6 of limiter 7 will not vary. Circuit 10 is therefore supplied with rectangular wave signal O6, equivalent to limiter output signal O4 without defect P3, from limiter 7, so that accurate peak detection signal O8 can be obtained which does not contain any peak detection signal other than information. |
