| 摘要 |
PURPOSE:To reduce phase advancing status associated with frequent drop outs by detecting the deviation of an optical means toward the average direction of delay, and by reducing the dividing ratio of a dividing circuit corresponding to the level of the detection output. CONSTITUTION:The reproducing signal obtained optically by reproducing the video disc record, undergoes a by-pass filter 1 and becomes an FM video signal. It also goes through a low-pass filter 2, and is inputted to an optical system controlling circuit 4 and a disc motor controlling circuit 5 as a reproducing pilot signal. If the reproducing pilot signal lacks due to the drop out, the divided output from a variable dividing circuit 10 delays and causes the phase advancing of the disc motor. However, the optical deviation is obtained from the output of an integral circuit 8, and the average output of it is inputted to a level dividing circuit 15 in order to modify stepwise the dividing ratio of the variable dividing circuit 10 by rate in accordance with the levels of the averaged output above. By this, the disc motor gradually lags in phase and hence the optical means is returned to the neutral position. |
