| 摘要 |
PURPOSE:To efficiently correct the distortion of bobbin winding even if horizontal frequency is changed by changing the amplitude of a parabolic wave for correcting bobbin winding distortion of a CRT display through a gain control circuit in accordance with the horizontal frequency change of a horizontal deflecting coil. CONSTITUTION:A saw tooth wave with a vertical period is converted into a parabolic wave by an integrator and the parabolic wave is supplied to the horizontal deflecting coil 7 through a gain control circuit 2 to correct the right and left bobbin winding distortion of the CRT display. On the other hand, the +B voltage of the coil 7 to be changed in proportional to the horizontal frequency of the coil 7 is supplied to the circuit 2 through a differential amplifier 3 to change the amplitude of the parabolic wave in accordance with the horizontal frequency. Said constitution makes it possible to correct the bobbin winding distortion efficiently even if the horizontal frequency is changed. |
