| 摘要 |
PURPOSE:To obtain correct data usually even if asymmetrical components are included in the waveform of a reproduced input signal, by controlling the reference voltage level of a comparator means by the difference signal between the first and the second detecting means. CONSTITUTION:The reproduced signal is sliced in the first comparator 1 by a signal where the voltage from a reference voltage source E1 and the feedback signal from the second comparator 7 are superposed. A counter circuit 4 or 4' is loaded with a center value D of the counter circuit 4 and it is latched in latch circuits 5 and 5'. When the reproduced signal voltage is inputted to the second comparator 7 having the differential amplifying constitution, a voltage corresponding to the difference of DC voltage is taken out. This signal is allowed to pass through a low pass filter circuit consisting of a resistor R2 and a capacitor C1 to prevent the change of even the reproduced signal including drop-out components or the like, and the reproduced signal is fed back to the reference voltage source E1. Thus, the reference voltage of the comparator 1 is changed to cancel the change based on the asymmetry of the reproduced signal, and the feedback signal does not include jitter components or the like. |
