| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the abnormity of a screen image due to disturbance of synchronization of the television receiver in the case of receiving a weak field signal or in the case of reproducing a software source with a copy guard signal included therein. SOLUTION: When the user selects a TV mode of the television receiver a microcomputer 1 outputs a low level signal, a TR 2 is conductive, resistance division between resistors R1, R2 is caused so as to decrease a response to noise at reception of a weak field signal by decreasing the gain for high frequencies. When the user selects a VIDEO mode of the television receiver, the high frequency response is enhanced, a fluctuation in a PLL circuit caused by a vertical synchronizing signal is constrained in a blanking period and a filter is selected so as to suppress a bent in longitudinal lines on an upper part of a screen in the case of reproducing a software source with copy guard.
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