Deutsche Thomson-brandt Gmbh

Thomson Licensing S.a.

Bernd Rekla

Gunter Gleim

Friedrich Heizmann

Friedrich Fuldner

G&uuml;nter Gleim

Dirk Carpentier

Guenter Gleim

A convergence method for color television receiver comprises the steps of emitting a test signal from a control circuit to a first convergence channel to generate a current of a predetermined intensity in a convergence coil assigned thereto. The control circuit emitting a zero signal to the other convergence channels to generate zero current in the assigned convergence coils. Measuring and comparing with a reference potential a potential at a reference point of each convergence coil of channels driven by the zero signal. Generating a reference signal responsive to the comparison step b), for each case for the relevant convergence channel and coupling to the control circuit. Repeating steps a) to c) for each convergence channel, the convergence channels being driven in an alternating fashion one after another once in each case by a test signal.

Method and apparatus for convergence correction in a television receiver

A Circuit for conditioning sync signals for devices for the line-by-line Display of video signals includes, a first input for horizontal sync signals (H sync, H sync), a second input for vertical sync signals (Vsync), and a delay stage. The delay stage outputs a signal (Vshift) which is delayed relative to the vertical sync signal (Vsync) by a specific delay time (reg). The circuit determines the timing of the horizontal sync signals (H sync, H sync) relative to the vertical sync signal (Vsync) and/or relative to the delayed signal (Vshift). The delay stage is designed in such a way that the delay time (reg) is adjustable.

Conditioning synchronization signals based on line-by-line display of video signals

A method for convergence correction in a television receiver and to a television receiver, in particular a projection television receiver having in each case one monochromatic picture tube for the three primary colours, red, green and blue, improves the quality of convergence correction. Each picture tube is assigned a correction device which comprises a convergence circuit. The convergence circuit is assigned a memory in which correction values for the convergence correction of the three picture tubes are stored. In accordance with the correction values, the convergence circuit generates output signals, which are output to a correction device, which in each case comprise at least one correction coil and, for each correction coil, one driver circuit. A correction current is applied to the associated correction coil in order to correct image defects of a picture tube. The convergence circuit also has control means for influencing the output signals output to the correction devices in such a way that the same correction is always effected on the picture screen for a specific correction value, independently of the gain of the respective driver circuit.

Method and device for convergence correction in a television receiver

The invention relates to a television receiver, in particular a projection television receiver having red, green and blue monochromatic picture tubes, the images of which are projected onto a picture screen. Each picture tube is assigned a correction device comprising a convergence circuit. The convergence circuit is assigned a memory in which correction values for the convergence correction of the three picture tubes are stored. In accordance with the correction values, the convergence circuit generates control signals, which are output to at least one correction coil where each correction coil has one driver circuit. A correction current is applied to the associated correction coil to correct image defects visible on each picture tube. The convergence circuit has control arrangement where the output signals coupled to the correction devices can be influenced in such a way that the same correction is always effected on the picture screen for a specific correction value, independently of the gain of the respective driver circuit. The invention also relates to a method for determining the control signal.

Device for convergence correction in a television receiver

A method is proposed for obtaining signals in electronic devices by means of interpolation between interpolation point values (W0 to W12), the interpolation point values (W0 to W12) being distributed linearly over a region. A number of interpolation values are calculated in each case at a specific interval between the interpolation point values (W0 to W12). The calculation of the interpolation values is then performed as follows: Firstly, a correction step value (a to 1) is determined in each case for an interval bounded by two interpolation point values (W0 to W12) by linear interpolation between these interpolation point values (W0 to W12) . These correction step values (a to 1) are calculated for all intervals. The calculation of the interpolation value in the current interval is then performed such that apart from the correction step value (a to 1) for the current interval use is also made at least of the correction step value (a to 1) of the preceding and/or of the following interval. As a result, the interpolation curve is laid smoothly through the intervals, and pronounced discontinuities in the gradient of the interpolation curve are avoided.

Method for obtaining signals in electronic devices by means of

A regulation circuit which guides a laser beam along the data track of a recording medium includes a first comparator which receives an HF signal and a first threshold signal. The HF signal is normally high and goes low when the laser scans a dirty or damaged area of the recording medium. The first comparator provides a first output signal when the HF signal is less than the first threshold signal. A second comparator receives a tracking error signal and a second threshold signal. The tracking error signal is normally low and goes high when the laser leaves the data track. The second comparator provides a second output signal when the tracking error signal is high and exceeds the second threshold signal. The first and second output signals are input to an AND gate which provides a signal indicating that the laser beam has left the data track when the first and second output signals are both high.

Track error control signal generation apparatus as for a disc player

Direction determining logic for a regulation circuit which guides a detection device along the data tracks of a recording medium receives an HF signal indicating when the detection device scans a dirty or damaged area of the recording medium, and a tracking error signal when the detection device leaves the track. The direction determining logic includes first and second multiple input terminal logic gates for respectively providing first and second complimentary output signals. A bistate logic circuit is selectively responsive to the HF signal and the tracking error signal and provides complementary output signals to one input terminal of each of the multiple input terminal logic gates. Other logic selectively inhibits the other input terminal of one of the multiple input terminal logic gates as the detection device scans a dirty or damaged area of the recording medium and the other of the multiple input terminal logic gates when the tracking device leaves the track.

Direction-determination logic as for a signal pickup in recorded signal

A system for controlling the number of data tracks crossed by the tracking head of a recording/playback device as the tracking head moves in a desired direction over a recording medium includes a counter having n output terminals. The counter is initially set to a count representative of the desired number of data tracks to be crossed as the tracking head moves in the desired direction. An further counter, also having n output terminals individually corresponding to the output terminals of the counter, is set to a predetermined count. Counting pulses are provided to the counter when the tracking head moves in the desired direction and to the further counter when the tracking head moves in a direction opposite from the desired direction. The output terminals are compared and a stop signal is generated when all terminals of both counters show that both counters are in the same state.

Track crossing method using dual counters

A servo control arrangement for an optical scanner for focusing a light beam onto a recording medium or for guiding the light beam along data tracks of the recording medium. Light reflected from the recording medium is directed onto a plurality of photodiodes which are connected to a differential amplifier. The amplifier takes differences of the output signals from the photodiodes to generate a servo signal having superimposed high frequency noise components from data recorded on the recording medium. The high frequency noise components are eliminated by short circuiting through a capacitor connected between the inputs of the differential amplifier, whereby the inputs of the differential amplifier become free of the high frequency noise components.

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Villingen-Schwenningen, Germany

Bernd Rekla