| 摘要 |
PROBLEM TO BE SOLVED: To provide a horizontal pincushion distortion correcting circuit which can appropriately operate regardless of the variation of an element or change of the temperature. SOLUTION: A horizontal pincushion distortion correcting circuit 10 incorporates an S-shaped capacitor CS, the terminal voltage of which is divided by means of resistors R1 and R2, and the high-frequency component contained in the terminal voltage is removed by means of a capacitor C4. The divided terminal voltage is given to the plus input terminal of a differential amplifier 18. On the other hand, a vertical parabolic voltage is given to the minus input terminal of the amplifier 18. The amplifier 18 outputs an amplified voltage proportional to the difference between the two inputted voltage to a PWM circuit 16. The circuit 16 controls the duty ratio during the turned on/off periods of an FET 14 based on the output voltage of the amplifier 18. Consequently, the pincushion distortion correcting circuit can be controlled appropriately regardless of the variation of an element or change of the temperature. Therefore, the circuit can appropriately make horizontal pincushion distortion correction. |
