| 摘要 |
PURPOSE:To extremely stablly and exactly remove a sag from an image signal by inverting relatively a revel detection signal and a video signal in the leading end part of a synchronizing signal, and adding them with each other. CONSTITUTION:In case a signal having a sag like a signal (a) is inputted to an input terminal 1, an adder 3 adds the input signal and a signal outputted from a DC amplifier 6, and a DC amplifier 4 inverts and amplifies the resulting signal and outputs to an output terminal 2 and to a SYNC synchronism, tip detection circuit 5. The circuit 5 detects the DC level and the sag of the SYNC tip of the output signal, and inputs the result to the DC amplifier 6. The DC amplifier 6 amplifies said DC level and sag, and outputs them to the adder 3. The DC signal (figure (b)) is feedbacked to the adder 3 hence comes lower if the DC level of the input signal comes higher. Therefore, the input DC level and the output DC level of the DC inversion amplifier 4 come stable. Also, the sag inputted to the adder 3 comes to have its polarity opposite that of the input signal after being subjected to the DC amplifier 4.
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