| 摘要 |
PURPOSE:To perform accurate and stable reading operation by outputting the peak value of an analog value detected right before tristate level variation discriminated by the positive and negative threshold value of the differential waveform of an analog waveform occurs successively. CONSTITUTION:The analog waveform read by a reproducing head 10 is passed through an amplifier 12, differentiated at a section 14, and then inputted to a zero-cross detector 16. The output of the section 14 is inputted to level comparators 18 and 20, whose outputs are inputted to an edge detector 32 through an FF30. The circuit 32 sends a signal (k) to an FF36 when the tristate level variation discriminated by the positive and negative threshold values of the differentiated waveform occurs successively. The peak signal (f) of the circuit 16 is inputted to the FF36 through a delay circuit 34. The FF36 detects only read data corresponding to the position of a correct peak securely and erroneous read data due to a pseudo peak is removed securely. Thus, reading operation with accurate and stable wide-range recording density and a readout speed is carried out. |
