| 摘要 |
PROBLEM TO BE SOLVED: To eliminate channel interference affecting video signal quality as much as possible without additional reference signals by using an adaptive equalizer trained by digital signals like teletext data transmitted accompanying video signals. SOLUTION: The video signals are sent through a window stage 3 to an evaluation stage 4 for digital data signals, the control output of the evaluation stage 4 is outputted to an adjustable filter unit 5, the filter characteristics of the filter unit 5 are changed by the digital data signals so as to minimize the interference of output signals and the influence of the interference fetched to the channel of the video signals is eliminated. Also, the output of the evaluation stage 4 is connected to the output of the adaptive equalizer 2. By using the window stage 3 and the evaluation stage 4, the operation of the characteristic change of the adjustable filter unit 5 is performed only when the digital signals are present, and when they are absent, the filter characteristics are fixed through a control line by corresponding signals.
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