Abstract: Display apparatus comprises a display screen. Drive means generates an image on the display screen in response to a video signal input from an external video source. The drive means comprises a memory for storing a gamma value and gamma correction means for modifying the input video signal as a function of a gamma value. Gamma variation means permits adjustment or the gamma value stored in the memory in response to a control signal input.

Abstract: An electron source having a cathode and a permanent magnet perforated by a plurality of channels extending between opposite poles thereof. The magnet generates, in each channel, a magnetic field which forms electrons received from the cathode into an electron beam for guidance towards a target. An electrode grid is disposed between the cathode and the magnet for controlling flow of electrons from the cathode into each channel. A magnetic field null region of each magnetic field is positioned at a location remote from the electrode grid. Because the null region is positioned remotely from the grid electrodes, flow of electrons can be improved without increasing electrode drive voltage.

Abstract: Display apparatus comprises a display screen and drive means for generating an image on the display screen in response to a video signal input from an external video source. The drive means comprises gamma measurement means having a test signal generator for generating a test signal to produce a test image on the display screen, and output detection means for generating a sense signal as a function of the test image produced on the display screen.

Abstract: An adaptor connection apparatus for a data processing system having at least first and second bus architectures and a guide for receiving first and second removable adaptors. Within the guide, first and second electrical contacts are provided for simultaneously connecting the first and second adaptors to the first and second bus architectures, respectively.

Abstract: An electron source comprises cathode means and a permanent magnet. A plurality of channels disposed in the magnet in a two dimensional array of rows and columns and extending between opposite poles of the magnet. The magnet generates, in each channel, a magnetic field which forms electrons received from the cathode means into an electron beam for guidance towards a target. Grid electrode means are disposed between the cathode means and the magnet for controlling flow of electrons from the cathode means into each channel. The grid electrode means comprises a plurality of parallel row conductors and a plurality of parallel column conductors arranged orthogonally to the row conductors. Each channel is located at a different intersection of a row conductor and a column conductor. Electric field isolation means reduces leakage of electric fields from each intersection.

Abstract: A display device having a cathode for emitting electrons and a permanent magnet. A two dimensional array of channels extends between opposite poles of the magnet. The magnet generates, in each channel, a magnetic field for forming electrons from the cathode into an electron beam. An electrode grid is disposed between the cathode and the magnet for controlling flow of electrons from the cathode into each channel. A screen has a phosphor coating having a plurality of groups of adjacent pixels facing the side of the magnet remote from the cathode. Each group corresponds to a different channel. A deflector sequentially addresses the electron beam from each channel to each pixel of the corresponding group.

Abstract: A Moire interference detection apparatus for a raster-scanned cathode ray tube display is provided. The apparatus comprises a band-pass filter for generating an output signal in response to a signal indicative of the pixel frequency of a displayed image in a direction of raster scan falling within the pass band of the filter. Control means varies the center frequency of the pass band of the filter in dependence on an active video period of the image in said direction of raster scan, the spacing of adjacent phosphor elements of the cathode ray display tube of the display in said direction of raster scan, and the scan size in said direction of raster scan.

Abstract: A display device having a cathode for emitting electrons and a permanent magnet. A two dimensional array of channels extends between opposite poles of the magnet. The magnet generates, in each channel, a magnetic field for forming electrons from the cathode into an electron beam. A screen receives an electron beam from each channel. The screen has a phosphor coating facing the side of the magnet remote from the cathode. The phosphor coating having a plurality of pixels each corresponding to a different channel and each having a plurality of different color sub-pixels. An electrode grid is disposed between the cathode and the magnet for controlling flow of electrons from the cathode into each channel.

Abstract: A conductive coating on the front surface of the display screen is used to determine the position of an object, such as a user's finger, touching the screen. Sensors at the edge of the conductive coating detect changes in the level of the ambient field pickup when the user's finger touches the display screen. The conductive coating may optionally be divided into blocks with separate connections to each block, or may have a resistivity profile so as to allow full X and Y co-ordinate determination of the position of the finger. Also, optionally, a stylus generating an electromagnetic field when in contact with the display may be used in place of the finger.

Abstract: Display apparatus comprises a display screen (400) and a drive circuit (401) connected to the display screen (400) to generate an image on the display screen (400) in response to an input video signal (R,G,B). A timer (405) generates a count in response to a clock signal. A detector (403,404,402) also receives the input video signal and resets the timer (405) on detection of a change in image content between successive frames of the input video signal (R,G,B). Control means (402) is connected to the timer (405) and to the drive circuit (401) for at least partially disabling the drive circuit (401) in response to the count stored in the timer (405) exceeding a predetermined threshold.

Abstract: An electric field cancellation system comprises a sensor (30) for generating an input signal (I) indicative of an unwanted electric field (E) radiating from a source (3), a variable gain amplifier (5) for amplifying the input signal (I) to produce an output signal (O), a radiator for generating a cancellation electric field (C) in anti-phase to the unwanted field (E) in response to the output signal (O) to at least partially cancel the unwanted field (E), feedback means (10) for generating an error signal (F) indicative of tile difference between the cancellation field (C) and the unwanted field (E), and control means (40) for varying the gain of the amplifier (4) to vary the output signal (O) in response to the error signal (F).

Abstract: The present electrical apparatus comprises an antenna for directing towards an electric field source to detect the electric field (E) to be reduced. The antenna is connected to amplifier for generating an output signal in response to an input signal from the antenna. The output signal is in anti-phase to the input signal. A radiator is connected to the amplifier for radiating a cancelling electric field (E') in anti-phase to the electric field (E) from the source in response to the output signal from the amplifier to at least partially cancel reduce the electric field from the source. The antenna, when directed towards the source, is positioned relative to the radiator and the source to detect both the cancelling electric field (E') from the radiator and the electric field (E) from the source. The input signal produced by the antenna is thus derived from the sum of the electric field (E) to be reduced from the source and the cancelling electric field (E') from the radiator.