| 摘要 |
PURPOSE:To obtain a suitable phase comparator for the tracking control of the CD system DAD reproducer especially with wide control band without adverse effect by noise by providing two detecting means and phase difference signal producing means. CONSTITUTION:Since phase difference signals U, D corresponding to the lag and lead of the phase of a detecting signal B to a tracking error detecting signal A are obtained respectively in this circuit, a tracking error control signal obtained by adding the phase difference signals U, D at an operational amplifier 32 via LPFs 30, 31 becomes a sawtooth wave and the control band is widened. Further, since the phase difference signals U, D are the comparison of areas in response to the phase lag and lead of the tracking error signals A, B substantially, even if pulsive noise is mixed at an optional time, almost no adverse effect is produced on the phase difference signals U, D, then the effect of noise is not received. |
