DEVICE FOR CORRECTING FLUCTUATION OF TIME AXIS

摘要

PURPOSE:To correct stably time axis by adding a simple switching circuit so as to increase the time constant of a PLL section and providing a circuit detecting missing of a regenerated synchronizing signal for improving the sensitivity of detection of a time axis error signal. CONSTITUTION:The regenerated synchronizing signal from a disc 13 of a video disc player is detected by a detector 14 and a demodulating circuit 16 and a regenerated horizontal synchronizing signal 1 separated by a synchronous separating circuit 17 is fed to the PLL section 23 and a sample holding circuit 6. The time axis error signal from the circuit 6 is applied to a drive circuit 9 via a phase compensating circuit 7 and an amplifier 8 so as to control the relative speed between the disc 13 and the reproducing means. A switching section 20 is provided to the input side of the PLL section 23 of this time axis fluctuation compensating device and the circuit 20 changes over a basic horizontal synchronizing signal 18 from a stable oscillator and the regenerated synchronizing signal 1 by using a switching signal 19 for correcting time axis. Further, the output side of a detector 14 is provided with a regenerated synchronizing signal missing detecting circuit 22, the sensitivity of detection of the time axis error signal is improved and the time axis correction is attained stably.