VERTICAL DEFLECTION DEVICE FOR CATHODE-RAY TUBE

PURPOSE:To remarkably improve the linearity of a displayed picture by providing a deflecting signal modulating means to correct a vertical deflecting signal according to a luminance signal to be supplied to a cathode-ray tube, and inputting the output signal of this deflecting signal modulating means to a vertical deflection circuit. CONSTITUTION:The deflecting signal modulating means 10 to correct the vertical deflecting signal 8 is constituted of a blanking removing part 11, an extracting part 12, an impedance converting part 13, a DC clamper 14 and a differential amplifier 15. Accordingly, when the voltage of the luminance signal Y of negative polarity falls so as to raise the luminance of a part of the screen of the cathode-ray tube 1, it decreases the amplifying gain of the vertical deflecting signal 8 so as to reduce the vertical deflecting signal 23 to the vertical deflection circuit 9, and acts in a direction to reduce a vertical amplitude, and corrects the extension of the amplitude following the fall of high voltage. In the case of the decrease of the luminance, it acts a reverse operation, and by correcting the vertical amplitude according to the luminance signal, the correction can be performed without detonating the linearity.