| 摘要 |
A variable band-pass filter circuit includes a variable band-pass filter which filters an input signal such as a chrominance signal. An output the variable band-pass filter is phase-compared with a reference signal in a phase comparator. An output of the phase comparator is applied to the variable band-pass filter as a control signal. The output of the variable band-pass filter is level-limited by a limiter and then applied to an adder which further receives the reference signal. One of the input signal arid an output of the adder is selected by a switch to be applied to an input of the variable band-pass filter. A reference signal component is removed by a sample hold circuit to be prevented from being outputted from an output of the variable ban-pass filter.
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