| 摘要 |
PROBLEM TO BE SOLVED: To accurately set an end point of time in a de-energizing state of a dynamic focus voltage for an automatic cathode-ray tube bias (AKB) measurement period. SOLUTION: A delay circuit, that includes a signal source for a blanking signal denoting a generating timing for a blanking period of a video signal and a horizontal line counter, delays a blanking signal by a plurality of horizontal periods, in response to the blanking signal and a horizontal frequency signal to generate a delayed signal. A switch Q15, included in a dynamic focus voltage generator 97, applies a dynamic focus voltage to a focusing electrode 17 when the switch is set to a 1st state, in response to the delayed signal or de-energizes application of the dynamic focus voltage, when the switch is in a 2nd state. The end point time of the de-energizing period of the dynamic focus voltage depends on the output signal of the counter.
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