| 摘要 |
PURPOSE:To reduce a pulse code reproduction error with simple constitution even in a modulation system which contains a large number of low band frequency components, by obtaining a differential of the reproduction outputs. CONSTITUTION:A reproduction output signal is supplied to a differential A/D converter 8, and a differential signal of the reproduction output signal is delivered to a transversal filter 5 after A/D conversion. This A/D converted signal undergoes the equalization of waveform through the filter 5 and is delivered to an extreme point phase detector 13. The detector 13 has an amplitude comparison level Xref and works only when Xi<=Xref is satisfied to an input signal series Xi. Then the detector 13 delivers the position information on the maximum or minimum value of the Xi in the form of the phase information to a synchronizing clock signal together with the extreme point phase signal. This phase signal is delivered to a data reproducer 7, and the reproducer 7 reproduces a pulse code. In such a way, the pulse code is detected out of the reproduction output signal by the differential detection. Thus the reproduction error of the pulse code can be reduced without using substantially the low band frequency component of the reproduction output signal. |
