| 摘要 |
PURPOSE:To secure the right-left symmetry of waveforms so as to reduce occurrence of peak shifts and the error rate of data, by changing readout signals passed through an LPF to pulses after passing through an all-band-pass filter. CONSTITUTION:Waveforms of signals read out from a medium by means of a magnetic head 1 are made narrow and sharp with a cosine equalizer 3 after amplification 2 and noises of the signals are reduced by controlling the band of the signals with an LPF 4. The readout signals are sent to a discrimination circuit after their group delay frequency characteristics are flattened by means of an all-band-pass filter 5 and they are changed to pulses by a pulse circuit 6. When the group delay frequency characteristics are flattened in such a way, the right-left symmetry of waveforms can be secured and, as a result, occurrence of peak shifts and error rates of data can be reduced.
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