| 摘要 |
A circuit for switching a video signal to a reference level, known as a "clamp circuit," minimizes changes in the basic brightness of the lines which occur during the retrace interval. The circuit includes first and second circuit stages operating with different time constants to supply the video signal to the video output tube. The first circuit stage is activated during a first chronological duration of the pulse pause of the video signal, so that the video signal is switched to a reference level. The second circuit stage is activated during a second chronological duration of the pulse pause, following the first chronological duration, so that the video signal is switched to the same or to a different reference level.
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