| 摘要 |
There is disclosed a VIDEO AUTOMATIC FOCUSSING SYSTEM in which a video signal from the television camera is directed to a band pass filter and then detected to produce a DC signal indicative of the video signal as band limited. The detected signal is directed to the inputs of a negative slope detector and peak detector. The detectors monitor the slope of the video signal to form the basis for controlling the motor to achieve automatic focussing on command.
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