Abstract: A method to obtain configuration data for a data processing apparatus by calculating (110) a time interval between the commencement of a mode (104) and a subsequent event (108). The calculated time interval is then compared (112) with one or more reference values (114). The result of the comparison is used to derive configuration data (116). The method may be further refined by including a calibration stage to reduce the error in the calculated time interval, thereby allowing comparison with a larger set of reference values (114), which in turn permits more configuration data to be derived from the calculated time interval.

Abstract: A data transmission system for short but frequent data pulses comprises a transmitter (10) and a receiver (12). The transmitter comprises a pseudo-random signal generator (16) which governs the time delay between successive timing points and a local oscillator (15) which controls the time of data transmission, and the receiver comprises a corresponding pseudo-random signal generator (22) and local oscillator (24). Power is applied to the receiver substantially only corresponding in time to the timing of the data bursts. Multiple collisions between adjacent systems operating on the same wavelength are avoided and the receiver is controlled to consume power only around the timing of the data bursts.

Abstract: A data transmission system for short but frequent data pulses comprises a transmitter (10) and a receiver (12). The transmitter comprises a pseudo-random signal generator (16) which governs the time delay between successive timing points and a local oscillator (15) which controls the time of data transmission, and the receiver comprises a corresponding pseudo-random signal generator (22) and local oscillator (24). Power is applied to the receiver substantially only corresponding in time to the timing of the data bursts. Multiple collisions between adjacent systems operating on the same wavelength are avoided and the receiver is controlled to consume power only around the timing of the data bursts.

Abstract: An arrangement for recording data, such as for example, teletext data, on standard domestic video recorders includes a teletext decoder and a microprocessor. The teletext decoder acquires selected teletext pages and passes them from its memory to the microprocessor over a bus as original standard teletex data packets. The microprocessor converts a teletext data packet into a plurality of data blocks, each of which is expanded to occupy a majority of an active line period. Thus the instantaneous data rate is reduced. The expanded data blocks are passed to video recorder circuitry via a shift register and switch. On replay, the microprocessor generates synthetic page and row headers to enable the teletext decoder to acquire data blocks from recording medium in the video recorder, as though the data blocks were standard teletext packets.

Abstract: In a television receiver having a wide aspect ratio display device (for example 16:9) which is arranged to receive and display a television transmission relating to a 4:3 aspect ratio picture, the receiver may be set to expand the 4:3 aspect ratio picture to cover the whole width of the display. Where this results in subtitles which are superimposed on the picture to be lost (since the expansion causes a portion of the bottom of the picture to be undisplayed) an arrangement (28) is provided to detect the presence of subtitles and shift them to a displayed portion of the display.

Abstract: A deflection circuit having particular application to a flat cathode ray display tube in which a channel plate electron multiplier is disposed parallel to, and spaced from, a cathodoluminescent screen and a low current, low voltage electron beam is scanned over the input side of the electron multiplier by means of a variable electrostatic field created between a planar array of substantially parallel elongate electrodes and the input side of the electron multiplier. In order to generate the variable electrostatic field a deflection circuit is provided having a plurality of ramp voltages generating stages, each stage being connected to a respective elongate electrode. The deflection circuit is operated in such a manner that the completion of the generation of a ramp voltage in one stage is used to trigger the next required stage.

Abstract: A line sawtooth deflection current generator with modulating means for the purpose of correcting the amplitude variations of the current produced, the said modulating means including a stage operating in the switching mode.