| 摘要 |
PURPOSE:To operate a rough adjustment servo system stably while maintaining the noise characteristics of a fine adjustment servo system excellently during time base corrections, by detecting the reproducing horizontal synchronizing signal in a reproducing composite synchronizing signal being within a prescribed pulse width range, and obtaining the reproducing horizontal synchronizing signal for a time base servo system for a reproducing signal. CONSTITUTION:The reproducing composite synchronizing signal A is inputted on an on-off gate 6 and an equivalent pulse eliminator 8, whose output is impressed to a gate pulse generator 15. The generator 15 generates a gate pulse C with pulse width gamma3 in response to the reproducing horizontal synchronizing signal. The gate 6 is controlled by the gate pulse C to allow only an input A during a period of the pulse width gamma3 of the gate pulse C. Its gate output G is the reproducing horizontal synchronizing signal for the tangential servo error signal generator 5 of the fine adjustment servo system at it is. The output of the eliminator 8 is inputted to a lock detector 11 together with a gate pulse D, which generates a lock detection signal when the reproducing horizontal synchronizing signal is present within the pulse width gamma2 of the pulse D to impress the pulse D to an NAND gate 7. The output E of this NAND gate 7 is supplied as a trigger input to an MMV14, whose output F is the reproducing horizontal synchronizing signal for the spindle servo error signal generator 2 of the rough adjustment servo system. |
