发明授权
US5555021A Compact television camera with switching noise prevention 失效
紧凑型电视摄像机具有开关噪声预防功能

Compact television camera with switching noise prevention
摘要:
An object of the present invention is to provide a compact television camera having a circuit that prevents switching noises by that a transistor of a power supply circuit being switched on for a dc-dc converter only during a blanking period eliminates the need for a transformer and shielding box for the dc- dc converter circuit and a low-pass filter circuit, thereby allowing the camera body to be made smaller. The compact television camera circuit, comprises in combination, a synchronizing signal generator (1), a timing signal generator (2) for generating a timing signal from said synchronizing signal generator (1) output, a vertical driver (3) and a horizontal driver (4) for generating vertical and horizontal scanning signals using the timing signal, a CCD pick-up device (5), a low-pass filter (8) for eliminating the high-frequency components of a video signal (b) output of said CCD pick-up device (5), and an output amplifier (11) for feeding out the video output signal (a). The low-pass filter (8) is an active low-pass filter formed of an emitter follower amplifier having a unity gain of 1. The power supply circuit (20) is formed of a charging circuit of the double-voltage charging type, wherein a trigger signal (c) of the synchronizing signal generator (1) for triggering said power supply circuit (20) is a signal (c1) or (c2) having a rising edge and a falling edge during a blanking period BLK of the video signal (b).
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