TRAPEZOID DISTORTION CORRECTING CIRCUIT

• Main Author: SEKO KAZUYUKI
• Format: Patent
• Language: English
• Published: 05.03.1993
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; PICTORIAL COMMUNICATION, e.g. TELEVISION

PURPOSE:To correct the trapezoid distortion by flowing the sawtooth current at the primary side of a trapezoid distortion correction transformer and changing continuously a secondary side inductance. CONSTITUTION:When the sawtooth current of the vertical deflection flows at a vertical deflection yoke LV1, the sawtooth current flows even at resistances R3 and R4 and at the inverse of terminal of an LL1 and the connection point of resistances R3 and R4, the sawtooth voltage occurs. The voltage to occur at the inverse of terminal of the LV1 is partially pressured by resistances R5-R7, the direct current cutting is performed by a C4, and inputted to the + terminal of an operational amplifier IC1. On the other hand, at the inverse of the terminal of the operational amplifier IC1, the voltage of the inverse of the terminal of the LV1 is partially pressured by the resistances R3 and R4, and the voltage in which the direct current cutting is performed by a capacitor C5 is inputted. The difference between the + terminal and the inverse of the terminal is amplified and outputted by the operational amplifier IC1. The output voltage is inputted to the temporary side of a trapezoid distortion correction transformer T3. By he current to flow at a primary side, a secondary side inductance is changed. As the result, the horizontal deflection current is gradually increased (or decreased) from the upper part of a screen to the lower part and the trapezoid distortion can be corrected.