Video signal frequency modulator having automatic control function and
controlling method therefor
    2.
    发明授权
    Video signal frequency modulator having automatic control function and controlling method therefor 失效
    具有自动控制功能的视频信号调频器及其控制方法

    公开(公告)号:US5655047A

    公开(公告)日:1997-08-05

    申请号:US715361

    申请日:1996-09-12

    CPC分类号: H03C3/09 H04N5/92

    摘要: A video signal frequency modulator having an automatic control function includes a reference generator for generating a sync tip level signal and a white peak level signal, a first switch for selecting one of the sync tip level signal, white peak level signal or a clamped video signal according to a mode control signal, a variable gain amplifier for amplifying the output of the first switch to a predetermined gain and converting the amplified result into a current, an adder for adding the output of the variable gain amplifier with a predetermined set value, an oscillator for frequency-modulating the output of the adder, a frequency detector for shaping and frequency-dividing the output of the oscillator, a microcomputer for comparing the output of the frequency detector with a predetermined reference frequency and outputting first and second control data and the mode control signal, a carrier frequency setting portion for controlling the magnitude of the predetermined set value according to the first control data, and a frequency deviation setting portion for controlling the predetermined gain according to the second control data.

    摘要翻译: 具有自动控制功能的视频信号频率调制器包括用于产生同步尖端电平信号和白色峰值电平信号的参考发生器,用于选择同步尖端电平信号,白色峰值电平信号或钳位视频信号之一的第一开关 根据模式控制信号,可变增益放大器,用于将第一开关的输出放大到预定的增益并将放大的结果转换为电流;加法器,用于将可变增益放大器的输出与预定的设定值相加, 用于对加法器的输出进行频率调制的振荡器,用于对振荡器的输出进行整形和分频的频率检测器,用于将频率检测器的输出与预定参考频率进行比较并输出第一和第二控制数据的微型计算机, 模式控制信号,用于控制预定设定值的大小的载波频率设定部 以及用于根据第二控制数据控制预定增益的频率偏差设置部分。