| 摘要 |
PURPOSE:To eliminate unnecessary inversion due to a saddle by differentiating a playback signal after passing it through an LPF, converting the output of a comparator which is inverted every time the signal crosses the zero level into a binary signal through an LPF, and delaying the inversion timing of the binary-coded output and sampling it. CONSTITUTION:The playback signal of a magnetic head 1 is passed through a preamplifier 2 and the LPF3 and differentiated by a differentiating circuit 4. The comparator 5 outputs a signal (c) which is inverted every time the differential output signal (b) crosses the zero level. The signal (c) is inputted to the LPF6 and then inputted to a limiter 7 having hysteresis, so that it is outputted as a binary-coded signal (e). Simultaneously, the signal (c) is inputted to a one- shot circuit 9, which generates a pulse signal (f) every time the signal (c) varies in level and supplies it to a delay circuit 10. The binary-coded signal (e) is sampled with the delay signal output (g) of the circuit 10 and a latch circuit 11 outputs a signal (h). Thus, unnecessary inversion due to a saddle is eliminated and read data (i) is outputted. |
