Deutsche Thomson-brandt Gmbh

Thomson Licensing S.a.

Bernhard Malota

Jacques Chauvin

Albert Runtze

A method for adjusting convergence in a projection television receiver, in which a marker contained in a projected image is adjusted by a manipulated variable to illuminate a photosensor arranged adjacent to the projection screen. The method employs two markers which are moved towards the sensor from opposite directions with a varying step size. The sensor supplies an output voltage indicating lighting by the two markers in conjunction with two mutually spaced manipulated variables. A mean value of the two manipulated variables is used as the manipulated variable for the marker.

Method for adjusting convergence in a projection television receiver

A set of coarse or initial convergence correction values for a model line of projection television receivers is defined in digital form prior to production using a fine grid or grating pattern. The set of coarse convergence correction values is digitally stored in all the receivers of the model line. A receiver-specific set of fine or final convergence correction values is defined in digital form for each receiver in the model line using a coarse grid or grating pattern. In each receiver, the receiver-specific set of fine or final convergence correction values is combined with the stored set of coarse convergence correction values. Convergence correction during subsequent operation of each receiver is based on the combined convergence correction values. Some of the coarse and fine convergence correction values can be located horizontally outside of the visible picture area of the receivers.

Method for correcting the convergence in a projection television receiver

An apparatus for electron beam deflection in a cathode ray tube, in particular in a picture tube of a television set, comprises a deflection coil arrangement for horizontal and vertical deflection of the electron beam, an auxiliary deflection coil arrangement, by means of which the electron beam can be influenced for the purpose of convergence correction, and a compensation coil arrangement for producing a magnetic compensation field. The compensation coil arrangement is arranged and designed such that the compensation field essentially compensates for the stray magnetic field of the deflection coil arrangement in the physical region of the auxiliary deflection coil arrangement.

Electron beam deflection apparatus using an auxiliary deflection coil

At high frequencies, a video amplifier draws a higher current and normally is biased to provide such current. However, since high frequencies are rarely encountered, the present circuit controls the operating point as a function of the frequency. More specifically, a controlled variable which controls the operating point of the amplifier stage is obtained in dependence on the frequency to which the amplifier stage is driven.

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Monchweiler, Germany

Bernhard Malota