发明授权
US4209808A Stabilized automatic brightness control network in a video signal
processing system including an automatic kinescope beam current limiter
失效
一种视频信号处理系统中稳定的自动亮度控制网络,包括自动显像管光束限流器
- 专利标题: Stabilized automatic brightness control network in a video signal processing system including an automatic kinescope beam current limiter
- 专利标题(中): 一种视频信号处理系统中稳定的自动亮度控制网络,包括自动显像管光束限流器
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申请号: US023964申请日: 1979-03-26
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公开(公告)号: US4209808A公开(公告)日: 1980-06-24
- 发明人: Leopold A. Harwood
- 申请人: Leopold A. Harwood
- 申请人地址: NY New York
- 专利权人: RCA Corporation
- 当前专利权人: RCA Corporation
- 当前专利权人地址: NY New York
- 主分类号: H04N5/57
- IPC分类号: H04N5/57 ; H04N5/59 ; H04N9/64 ; H04N5/68
摘要:
A video signal processing system is disclosed including a sample and hold comparator arranged in a closed control loop with a video channel including a video amplifier for the purpose of providing automatic brightness control, and an automatic kinescope beam current limiter. The beam current limiter is coupled to a first point in the amplifier for controlling the amplifier signal gain to limit excessive beam current demand in a first control mode. In a second control mode, the beam current limiter cooperates with the automatic brightness control network to control the D.C. output level of the video amplifier in the presence of excessive beam current demand. The comparator response time is slow relative to transient variations of the D.C. level at the amplifier output induced by beam limiter action in the first control mode, but is otherwise sufficient to permit compensation of relatively long term variations in the output D.C. level. Compensation of the transient D.C. variations is provided by coupling transient beam limiter control voltages developed in the first control mode to a second point in the amplifier, for opposing transient D.C. level variations which would otherwise appear at the amplifier output in response to beam limiter action.
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