| 摘要 |
PURPOSE:To control the tracking with high accuracy without producing any noise component, by usng the signal obtained by giving a synchronizing amplitude wave detection to a reproduced tracking signal by a reference signal as a tracking control signal. CONSTITUTION:The tracking signal fp1 is supplied to a synchronizing AM wave detector 111 and turned into a full-wave rectifying signal (e) to be supplied to a switch circuit 13 after being smoothed through a smoothing circuit 121. A tracking signal fp2 receives a synchronizing AM wave detection by a rectangular wave signal of a phase equal (or opposite) to the tracking signal fp2 which is supplied from a 1/4 frequency divider 92 through a synchronizing AM wave detector 112 and is smoothed by a smoothing circuit 122 to be supplied to the circuit 13. The signals supplied from the circuits 121 and 122 are added together through an adder 15 and supplied to an AGC circuit 4. Thus an AGC is applied so that the sum of the tracking control signal to the signal fp1 and that to the signal fp2 is always constant. |
