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    Device for receiving closed captioned broadcasts
    2.
    发明授权
    Device for receiving closed captioned broadcasts 失效
    用于接收隐藏式字幕广播的设备

    公开(公告)号：US5347365A

    公开(公告)日：1994-09-13

    申请号：US948684

    申请日：1992-09-22

    申请人： Masami Harigai ,  Hiroyasu Kishi

    发明人： Masami Harigai ,  Hiroyasu Kishi

    IPC分类号： H04N5/06 ,  H04N7/025 ,  H04N7/03 ,  H04N7/035 ,  H04N5/445

    CPC分类号： H04N5/44513

    摘要： A synchronizing/separator circuit separates a horizontal synchronizing signal and a vertical synchronizing signal contained within a television signal. A phase locked loop synthesizes a clock signal at 32 fH by phase locking the horizontal synchronizing signal with a divided version of the 32 fH clock signal. The phase locked loop includes a voltage controlled oscillator (VCO) responsive to the phase comparison to perform the phase lock. A circuit separates the run-in clock and caption data in horizontal scanning period 21 H in the vertical blanking interval. A phase comparator receives the run-in clock and phase compares it with the 32 fH clock to produce an alternating control signal which is applied directly to the voltage controlled oscillator for rapid phase locking of the voltage controlled oscillator in preparation for decoding the caption data. The voltage controlled oscillator is controlled by the charging and discharging rate of a capacitor charged by a constant current source. The control signal varies the charging and discharging rate of the capacitor to effect rapid phase lock to the run-in clock.

    摘要翻译： 同步/分离器电路分离电视信号中包含的水平同步信号和垂直同步信号。 锁相环通过用32 fH时钟信号的分频版本锁相水平同步信号，以32fH合成时钟信号。 锁相环包括响应于相位比较的压控振荡器（VCO）来执行锁相。 电路在垂直消隐间隔的水平扫描周期21H中分离输入时钟和字幕数据。 相位比较器接收输入时钟，并将其与32 fH时钟相比较，以产生交流控制信号，该交流控制信号直接施加到压控振荡器，用于对压控振荡器进行快速锁相，以准备对字幕数据进行解码。 压控振荡器由恒定电流源充电的电容器的充放电率来控制。 控制信号会改变电容器的充电和放电速率，从而实现快速锁相到导入时钟。