Abstract: An apparatus and a method for protecting a video display device, having an anode and a cathode, against excessive beam current conditions. In particular, the present invention protects the video display device against zero-biasing of the device, wherein the cathode driver circuit is supplied by a plurality of power supplies and the loss of anyone of the power supplies causes zero-biasing of the cathode.

Abstract: A signal processor which provides non-linear transfer functions provides a processor output and non-linear inflection points that are referenced to a common bias. The processor output and the non-linear inflection points each exhibit rejection to time variant common-mode variations.

Abstract: A video processing system includes a video output driver stage which is capable of automatically self-regulating the peak beam current output provided to a display. The system includes a video output driver stage with a video signal input and a video signal output for providing an amplified video signal. The video output driver stage comprises means for amplifying the video signal input to form the video signal output and conveying the amplified video signal output to the image reproducing display device. The system further comprising a sensing output for providing thereat a sensed signal representative of current conducted by said image reproducing display device. The system also includes a sensing and control means for sensing the sensed signal and for providing a feedback signal to an input component of the video output driver stage for limiting the current conducted by said image reproducing display device to a predetermined value.

Abstract: A method and system for implementing a screen saver function is described. A peak value of a characteristic such as beam current magnitude of a video signal being processed is determined. An average value of the same characteristic of the video signal is also determined. Changes in this average value is additionally monitored. Therefore, the characteristic of the video signal is adjusted only if the peak value exceeds a first threshold and a change less than a second threshold is detected in the average value.

Abstract: A signal processor which provides non-linear transfer functions provides a processor output and non-linear inflection points that are referenced to a common bias. The processor output and the non-linear inflection points each exhibit rejection to time variant common-mode variations.

Abstract: Unintentional emissions are controlled responsive to the spectral content of the display signal. A video display apparatus comprises a cathode ray tube responsive to a video signal. A processor controls a bandwidth of the video signal coupled to the cathode ray tube in response to an emission control signal. A generating device is coupled to the processor for generating the emission control signal responsive to a component of the video signal.

Abstract: Generation of unintentional emissions are controlled by analysis of display signal content processed for scanning beam velocity modulation. An apparatus for scanning beam velocity modulation comprises a scanning velocity modulation signal processor for generating an scanning velocity modulation deflection signal responsive to a scanning velocity modulation signal. A generator supplies a feed forward signal to the processor for controlling the scanning velocity modulation deflection signal amplitude in response to a component of the scanning velocity modulation signal.

Abstract: Unintentional emissions are controlled responsive to the spectral content of the display signal. A video display apparatus comprises a cathode ray tube for video image display. A processor controls a magnitude of a video image display signal coupled to the cathode ray tube for display in response to an emission control signal. A generating means is coupled to the processor for generating the emission control signal responsive to a component of the video image display signal.

Abstract: Display apparatus includes a kinescope cathode current sensor (18) coupled to a load (200) for developing a beam current measurement pulse during a beam current measurement interval. Overshoots in the pulses are suppressed by a pulse correction circuit (300) comprising a first capacitor (Ca) coupled from the load circuit (200) to a source of reference potential (Gr) via a switch (Q300); and a control circuit (Ca, Ra, Rb), responsive to the presence of the overshoot, for closing the switch for a predetermined length of time and for opening the switch otherwise.

Abstract: A grid kick circuit for applying beam cut-off bias to the grid of a kinescope to provide spot burn protection. The circuit includes a first switching circuit having an output coupled to a first electrode of a grid kick capacitor and a second switching circuit having an output coupled to a second electrode of the capacitor and the grid. When beam blanking is not desired, charging current is supplied to the capacitor through a first current path from a first voltage source while the second switching circuit regulates the voltage at a second electrode of the capacitor and the grid. Current for the second switching circuit is provided by a second current path which is coupled to the first voltage source and is independent of the first path.

Abstract: An AKB interface apparatus in a display system (10), includes a video signal processing IC (12) having outputs coupled via respective kinescope driver ICs (18,20,22) to respective kinescope cathodes (K1,K2,K3) for display of a color image, the signal processing IC having an input 27 for receiving an AKB input signal, the driver ICs having respective outputs (28,30,32) providing respective cathode current indicating signals (RP,GP,BP) An interface circuit (100) couples the cathode current indicating signals to the AKB input of the signal processing IC. The interface circuit comprises a load circuit (110) for generating a load voltage (Vo) in response to at least one of the cathode current indicating signals. A leakage correction circuit (130), responsive to said load voltage (Vo), feeds back a leakage correction current (Io) to the load circuit.

Abstract: Supplementary grid blanking and spot burn protection are provided in a receiver/monitor (10) by a grid bias control circuit (50) including a blanking signal generator (60) that produces a blanking output signal (S1) devoid of any picture representative component whenever a vertical blanking signal (VB) or a horizontal blanking signal (HB) is present. A capacitor (C1) strips DC from the blanking signal and the resultant signal (S2) is applied to a modulation input (84) of a grid bias generator to produce an output grid bias reference voltage (Vr) modulated by the AC component of the blanking signal. The reference voltage (Vr) is coupled via a spot burn protection circuit (100) and a grid coupling circuit (120) to the control grids of three projection kinescopes (16, 18, 20).

Abstract: A direct current focus voltage applied to a focus electrode of a cathode ray tube that produces a blue image is set to slightly defocus the blue image for increasing the blue beam spot size. The increase in the blue beam spot reduces the saturation and allows brighter blue and increased blue video drive range. A passive network is coupled between an ultor electrode and the focus electrode to provide tracking of focus voltage-to-ultor voltage ratio. The tracking prevents voltage fluctuation of the ultor voltage produced by video loading from disturbing uniform defocussing in the entire blue image.

Abstract: Video signals to be displayed are applied via a video driver amplifier to the cathode electrode of a kinescope. A beam current sensor, also coupled to the cathode electrode, provides a beam current indicating signal. An AKB regulator, responsive to the beam current indicating signal, supplies a black level correction signal to the driver amplifier for regulating the black level of images displayed by the kinescope. A screen grid supply system is provided for controlling the G-2 (screen grid) voltage of the kinescope as a predetermined function of the black level correction signal thereby forming with the AKB regulator a dual feedback loop for providing black level regulation by both the driver amplifier and the screen grid thereby maximizing or extending the overall black level control range.