| 摘要 |
PURPOSE:To stabilize control accuracy, responsibility and control by generating a control signal according to the difference between a digital video signal and a reference signal in a prescribed period of the video signal and reproducing a direct current component of an analog video signal. CONSTITUTION:The analog video signal 11 inputted from an input terminal 1 is direct current reproduced in a control circuit 2, and transmitted to an integration circuit 6 as a timing lock 19 in which a start time and a duration can be set optionally by the timing circuit 9 of the analog video signal 12. It is converted into the digital video signal 13 by a sampling clock 20 inputted from a clock input terminal 10 in an A/D converting circuit 3, transmitted to a subtraction circuit 5, the level difference from the reference signal 14 set by a reference setting device 4 is calculated and transmitted to the integrations circuit 6. Then, a difference signal 15 is integrated according to the timing clock 19, an integration signal 16 is analog converted in a D/A converting circuit 7, transmitted to a control signal generating circuit 8 and a control signal 18 capable of controlling so as to approach the pedestal level of the analog video signal 12 to the level of the reference signal 14 and stabilize is generated and transmitted.
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