| 摘要 |
PURPOSE: To enable easy and sure recording/reproducing operation of data and also to consecutively reproduce the data. CONSTITUTION: A signal P by a side beam is converted into a signal DP by a circuit 23 and supplied to a PLL circuit 25 to produce a clock signal CLK. A signal DR is produced by a reproducing circuit 26 in accordance with the signal DP and signal CLK and supplied to a terminal 29a of a switching device 29. A signal Q by a main beam is converted into a signal DQ by a circuit 24, and a signal DN is produced by a reproducing circuit 27 in accordance with the signal DQ and signal CLK and supplied to a terminal 29b. When the signal DQ is not detected by a detector 28, the signal DR is selected by the switching device 29, meanwhile the signal DN is selected when the signal DQ is detected. The selected signal is demodulated by a demodulator 30 and supplied to a system control circuit 31, then the updated data are consecutively supplied to an outside device. The data recording is executed by supplying the data to a driving circuit 34, after modulated by a modulator 32 and also synchronized with the signal CLK by a synchronizing circuit 33. |
