Abstract: In indication and image reproduction apparatus, the ambient brightness must be taken into account for an optimum reproduction quality. This requires an optical sensor, which is associated with additional technical outlay. The invention relates to a circuit which allows the ambient brightness to be determined by means of a sensor that is already present in the device, for the reception of data or control signals. In particular for apparatus appertaining to consumer electronics.

Abstract: A method for generating display correction waveforms for a CRT display comprises the steps of selecting one of a plurality of trace portions for forming part of a correction waveform, the trace portions having different average values. Completing each of the correction waveform by combining each selected trace portion with a respective retrace portion such that all completed correction waveforms have a predetermined average value. The correction waveforms may have vertical and/or horizontal rates.

Abstract: 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.

Abstract: In indication and image reproduction apparatus, the ambient brightness must be taken into account for an optimum reproduction quality. This requires an optical sensor, which is associated with additional technical outlay. The invention relates to a circuit which allows the ambient brightness to be determined by means of a sensor that is already present in the device, for the reception of data or control signals.

Abstract: A method for generating display correction waveforms for a CRT display comprises the steps of selecting one of a plurality of trace portions for forming part of a correction waveform, the trace portions having different average values. Completing each of the correction waveform by combining each selected trace portion with a respective retrace portion such that all completed correction waveforms have a predetermined average value. The correction waveforms may have vertical and/or horizontal rates.

Abstract: For control and correction of deflection parameters especially of convergence, a grid pattern is displayed on the picture screen of a television device. For control of the convergence parameters and the evaluation of the correction values the crossing points of the grid pattern are marked by a cursor. The cursor is formed by at least one irregularity in the grid pattern being, regular otherwise. The irregularity may consist in an omission within the grid pattern like an interruption within one horizontal or vertical grid line. An image signal generator for the grid pattern with position cursor includes a raster generator, a grid generator, a cursor generator, and means for combining a grid signal from the grid generator and a cursor signal from the cursor generator so as to inhibit the grid signal corresponding to locations on the grid pattern where the position cursor is visible by an absence of display of portions of the grid pattern.

Abstract: 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 (H1sync, H2sync), 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 (H1sync, H2sync) 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.

Abstract: A memory and a switchable digital filter supply different numbers of digital distortion correction values. The supplied distortion correction values are converted to an analog distortion correction signal. A passive, analog low pass filter for the analog distortion correction signal generates an analog deflection signal. The low pass filter is optimized only for those of the analog deflection signals having a given sample rate. A controller varies the different numbers of the supplied distortion correction values to maintain the given sample rate of the analog deflection signal for different horizontal scanning rates. The controller selectively implements respective operating modes for different horizontal scanning frequencies in which no interpolated distortion correction values are supplied or different numbers of interpolated distortion correction values are supplied.

Abstract: In a video display, correction data for a digital convergence arrangement are stored in a first non-volatile memory. During power turn on procedure, the correction data are read out of and stored in a volatile memory. During each deflection cycle, the data stored in the volatile memory are successively read out and applied to an auxiliary convergence winding. When a parity error is detected in the read out data, an output and/or an input of a convergence amplifier is actively disabled to prevent a disturbance of a screen of the cathode ray tube.

Abstract: A circuit for correction of deflection errors in a television set, in which a correction current having alternate forward-sweep and flyback periods is supplied to a correction coil for an error parameter. An amplitude of the correction current is reduced during a time window which corresponds to the flyback period and in which no visible picture is displayed.

Abstract: A method for generating display correction waveforms for a CRT display comprises the steps of selecting one of a plurality of trace portions for forming part of a correction waveform, the trace portions having different average values. Completing each of the correction waveform by combining each selected trace portion with a respective retrace portion such that all completed correction waveforms have a predetermined average value.

Abstract: A circuit arrangement with a digital controller for operating an electric motor and a method for starting an electric motor are disclosed. Electric motors require a considerably higher current immediately after they have been switched on and during the running-up phase because of the inductance of the motor windings. In order to increase the control sensitivity of the controller for the normal operation, the control range of a digital controller is switched over into a higher current range for the running-up phase. For the normal operation of the motor, the control range of the controller is switched back again into a lower current range. As a result, the control sensitivity of the controller is completely available for the normal operation of the motor.

Abstract: In a video display, correction data for a digital convergence arrangement are stored in a first non-volatile memory. During power turn on procedure, the correction data are read out of and stored in a volatile memory. During each deflection cycle, the data stored in the volatile memory are successively read out and applied to an auxiliary convergence winding. When a parity error is detected in the read out data, an output and/or an input of a convergence amplifier is actively disabled to prevent a disturbance of a screen of the cathode ray tube.

Abstract: 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.

Abstract: A switchable digital filter interpolates distortion correction values. The distortion correction values together with interpolated distortion correction values are supplied as an output. Proper operation of the digital filter is disturbed by transient signals occurring during horizontal retrace. The digital output is converted to an analog convergence correction signal. The digital to analog converter has an operating frequency and generates a transient signal during horizontal retrace as the operating frequency increases due to an increased horizontal scanning rate. A low pass filter receives the analog convergence correction signal and generates an analog deflection signal. An auxiliary deflection coil is driven by the analog deflection signal. The digital filter is switched off during the horizontal retrace. The digital filter is thus protected from disturbance by the transient signal and the digital to analog converter is protected from exceeding a maximum operating frequency.

Abstract: 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.

Abstract: A method and apparatus for obtaining correction values for convergence setting in video projection devices includes calculating the correction values for the individual video lines at least in part by interpolation between correction interpolation point values. The correction interpolation point values are in this case distributed in the form of a grid over the screen area of the video projection device. During the calculation of correction values for the video lines of a first field of the video frame, a respective set of two intermediate or final values for the interpolation is calculated, which set is applicable to neighbouring lines in different video fields, but in each case only one intermediate or final value is used for the convergence correction in the current video line. As a result, optimal convergence correction can be set for each video line without a high memory outlay and without high computing complexity.

Abstract: Method and circuit arrangement for commutation of a multiple winding electric motor. Particularly when they are operated with square-wave signals, multiple winding electric motors require effective interference voltage suppression for many applications. The invention specifies a method and a circuit arrangement by means of which trapezoidal waveform control signals are produced upstream of the respective output amplifiers, so that the motor is driven with low impedance, as a result of which there is no need for additional suppression means. The trapezoidal waveform control signals are composed of an operating voltage or a corresponding signal, a reference potential and a triangular waveform ramp voltage, using switching means.

Abstract: A temperature monitoring process and device for controlling the operation of an recording and playback device in such a way that overheating is avoided. A temperature threshold is provided above which an economical operation mode is switched in, reducing power consumption and further heating.

Abstract: A method of breaking a motor includes the step of applying a pulse width modulated signal to the winding of the motor. A switching voltage is used to intermittently reverse the poles of the motor for selected time periods. The time periods are separated by pauses the duration of which is dependent upon the breaking force needed to stop the motor.