Deutsche Thomson-brandt Gmbh

Jaques Chauvin

Gunter Gleim

Friedrich Heizmann

Rainer Schweer

A grid correction circuit for a television receiver includes a first memory for storing correction values for correcting the deflection current of the television receiver. A second memory perodically provides a test signal to a correction coil to correct the deflection of the television receiver. A switch periodically selectively connects the first memory to the correction coil and a correction current flows through the correction coil. The switch also periodically connects the second memory to the correction coil and a test current flows through the correction coil. An impedance is responsive to the correction coil and produces a correction voltage and a test voltage in response to the correction current and the test current respectively. A comparator receives the test voltage and compares the test voltage to a reference voltage and provides an output voltage having a first level when the test voltage is below the reference voltage and a second level when the test voltage is above the reference voltage. A processor receives the output voltage and changes the correction voltage to incrementally reciprocate above and below the reference voltage by a preslected increment to maintain the correction voltage at substantially the same level as the reference voltage over a long time period.

Grid correction circuit for TV sets

A system for adjusting the position and size of a picture generated by deflecting a light source in response to a deflection current and displayed in a picture area larger than the picture includes sensors for sensing the picture arranged outside the picture and within the picture area. First and second differential amplifier both have an inverting and noninverting input terminal. A deflection voltage proportional to the deflection current is applied to the noninverting input terminal of the first differential amplifier and to inverting input terminal of the second differential amplifier. A first reference voltage is applied to the inverting input terminal of the first differential amplifier to produce a positive correction pulse in accordance with the difference between the deflection voltage and the first reference voltage. A second reference voltage is applied to the noninverting input terminal of the second differential amplifier to produce a negative correction pulse in accordance with the difference between the deflection voltage and the second reference voltage. A correction signal generator is responsive to the correction pulses and provides correction signals to the deflection circuit.

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Monchweiler, Germany

Jaques Chauvin