| 摘要 |
PURPOSE:To eliminate the effect of temperature even with no adjustment, by generating a gate signal with a digital counter and using a clock signal used for the digital counter in common for a reference signal of a servo circuit. CONSTITUTION:An output level of the digital counter 38 goes to L0, when it counts n2(=tau2/fCP, where fCP is clock frequency) sets of clocks. The tau2 is selected between H/2-H, where H is the horizontal scanning period. Then, there exists an equalizing pulse at the vertical synchronizing section, a set input is impressed before the count is finished and the counter output keeps Hi. The output of the counter 38 is applied to a counter 39 and an output of the counter 39 is inverted at an inverter 40, then a gate signal is obtained. Since the output of the reference clock signal generating circuit for servo is used in common for the clock signal, the oscillating circuit is not especially required for the provision. |
