Abstract: A video signal compression system includes motion compensated predictive compression apparatus for compressing respective frames of video signal according to either intraframe processing or interframe processing on a block by block basis to generate blocks of compressed data and associated motion vectors. A compressed signal formatter arranges the blocks of compressed data and the associated motion vectors according to a desired signal protocol wherein motion vectors of interframe processed frames are associated with corresponding blocks of compressed data and motion vectors of intraframe processed frames are associated with blocks substantially adjacent to corresponding blocks of compressed data. The motion vectors are included with intraframe compressed data to facilitate error concealment at respective receiver apparatus.

Abstract: Video signal compression apparatus includes a memory for storing two fields of image data and providing fields of image data separated by one frame intervals. Image data from corresponding fields of successive frames are subtracted to generate field differences. The field differences are accumulated over respective field intervals, and the sum is compared against a predetermined value. If a sum of differences over a field is less than the predetermined value, the most recent field is considered to be redundant and may be excised. After respective fields are excised, frames of video signal are composed from the remaining fields. The field types (e.g., odd or even) of the fields in the memory are determined, and the data is accessed from the respective fields in memory such that data from odd and even fields occupy odd and even lines in the composed frames respectively.

Abstract: A rate controlled VBR quantizing system includes a quantizer for quantizing partially compressed video data and further apparatus for monitoring the amount of compressed output data. Dependent upon the amount of compressed output data being lesser or greater than a predetermined value, the quantizer is conditioned to operate in a fixed quantization mode, or a mode wherein only selected blocks of data in respective frames are adaptively quantized, respectively.

Abstract: A phase-lock-loop circuit for generating a clock signal at a frequency higher than a horizontal frequency of a video signal includes a phase detector. The phase detector includes a flip-flop that is set when a horizontal sync pulse occurs. An output of a counter that provides frequency division is decoded for resetting the flip-flop in each horizontal period. Other than for the flip-flop, and for the counting stages of the counter, only combinational logic components are used for producing a phase error indicative signal that is coupled via a low-pass filter to a control input of an oscillator of the phase-lock-loop circuit.

Abstract: The present invention provides an improved color picture tube having a viewing screen and a shadow mask mounted adjacent to the screen. The mask has an apertured contoured portion and a peripheral skirt. The improvement comprises the skirt having a reverse bend therein, wherein a first portion of the skirt that connects with the apertured contoured portion extends away from the screen and a second portion of the skirt more remote from the apertured contoured portion extends towards the screen.

Abstract: The method of electrophotographically manufacturing a screen assembly on an interior surface of a faceplate panel for a color CRT, according to the present invention includes the step of forming a photoreceptor by sequentially coating the surface of the panel with a conductive solution to form a volatilizable conductive layer and then overcoating the conductive layer with an organic photoconductive solution comprising a suitable resin, an electron donor material, an electron acceptor material, a surfactant and an organic solvent to form a volatilizable photoconductive layer.

Abstract: Variable length codewords representing high definition television image information are processed by a codeword analyzr for prioritizing codewords within a predetermined codeword group. A single FIFO rate buffer conveys codewords subject to analysis to the analyzer. A succeeding codeword group is written into the buffer when a current codeword group is being analyzed, at which time buffer read out is inhibited. In an illustrated embodiment, buffer read out is inhibited, and codeword analysis begins, when MPEG Picture Start or Slice Start codewords associated with the succeeding codeword group approach the buffer output. Buffer read out is enabled at the end of the analysis interval.

Abstract: A compression/decompression system includes a source of (1:1 60 Hz) non-interlaced scanned video signal. A preprocessor constructs (2:1 60 Hz) interlaced scanned video signal from the non-interlaced scanned video signal by selection of alternate lines of successive non-interlaced image signals. The interlaced scanned video signal is compressed according to an MPEG protocol of I, P and B frame compression algorithms. I, P and B frame compression is performed such that there are an odd number, greater than one, of B-frames between successive I/P frames (for example the sequence of compressed frames may conform to I, B1, B2, B3, P, B1, B2, B3, P, B1, B2, B3, I, B1, . . . etc). The I compressed frames, the P compressed frames and alternate B compressed frames (the frames B2 in the exemplary sequence) selectively form a primary compressed (2:1 30 Hz) interlaced video signal for reproduction by interlaced scanned receivers. The intervening B-frames selectively form a secondary compressed video.

Abstract: A select line scanner for a liquid crystal display includes a plurality of cascaded stages each having an input terminal and an output terminal. Each stage includes a push-pull output circuit including pull up and pull down transistors driven with separate control signals. A further transistor has its conduction path coupled between the control electrode and a point of potential of sufficient value to turn the pull up transistor off. The control electrode of the further transistor is coupled to an output of a succeeding one of the cascaded stages to insure that the output of the respective stage cannot drift to an on state.

Abstract: The invention relates to a method of electrophotographically manufacturing a luminescent screen assembly for a color CRT by utilizing materials whose volatilizable constituents are substantially completely baked-out in the same step in which the faceplate panel is frit sealed to the funnel of the tube envelope. This method eliminates a dedicated panel bake before frit sealing of the panel to the funnel.

Abstract: A full wave rectified AC mains supply voltage is produced from an AC mains supply voltage without low-pass filtering. The rectified voltage is developed in a winding of a flyback transformer. The winding of the flyback transformer is also coupled to a switching transistor that generates in the winding a first plurality of current pulses at a frequency that is higher than the frequency of the mains supply voltage. The current pulses energize a load circuit. A capacitor voltage is coupled via a second switching transistor to the winding to produce in the winding a second plurality of current pulses that energize the load circuit during a portion of the period of the mains supply voltage that does not occur in the vicinity of the peak of the mains supply voltage. When the second plurality of current pulses are generated, the mains supply voltage is decoupled from the first winding.

Abstract: Organ pipes distortions, caused by parasitic ringing in a horizontal deflection current are suppressed by forming a current pulse in a current injection arrangement. The current pulse is coupled to a junction terminal between a terminal of the horizontal deflection winding where a high retrace pulse voltage is developed and a low voltage terminal of a linearity correction inductance. A high voltage terminal of the linearity correction inductance is coupled to a horizontal output transistor. The current pulse begins prior to the end of retrace and ends during the trace interval. A modulation network is coupled across the linearity correction inductance for providing a low impedance current path to the current pulse.

Abstract: An East-West switching transistor is coupled between a flyback transformer primary winding and a horizontal deflection output transistor circuit to control retrace energy to obtain an East-West modulation of the deflection current amplitude as required for East-West pincushion raster correction. The East-West switching transistor isolates a retrace resonant circuit that includes a horizontal deflection winding from a flyback resonant circuit that includes the flyback transformer during a portion of retrace. The deflection winding is coupled to a common conductor to permit the use of a retrace voltage sample, developed in the deflection winding and coupled to the East-West switching transistor, to control the switching operation in a manner that bypasses the flyback transformer. A resistor coupled in series with the primary winding develops a voltage, during trace, that is indicative of beam current.

Abstract: A compression/decompression system includes a source of non-interlaced scanned video signal. A preprocessor constructs interlaced scanned video signal from the non-interlaced scanned video signal by selection of alternate lines of successive non-interlaced image signals. The interlaced scanned video signal is compressed according to known methods to generate primary compressed video data. The primary data is decompressed by known processes, inverse to the compression processes, to regenerate the interlaced scanned frames. Interlaced scanned video signal, corresponding to the intervening lines of the non-interlaced scanned video signal, which were not included in the primary interlaced scanned video signal, is predicted from the decompressed frames of video signal. In addition the intervening lines of the original non-interlaced scanned video signal, which were not included in the primary interlaced scanned video signal, are formed into secondary interlaced scanned video signal.

Abstract: Elements of the compressed video signal which are of greatest importance to signal decompression are set a plurality of times in redundant transport cells. Media error codes are concatenated to the redundant data such that when and if such redundant data is applied to the corresponding decompressor, the media error code will automatically force the decompressor to resynchronize.

Abstract: The method of electrophotographically manufacturing a screen assembly on an interior surface of a faceplate panel for a color CRT, according to the present invention, includes the steps of sequentially coating the surface of the panel with a conductive solution to form a volatilizable organic conductive layer and then overcoating the conductive layer with a photoconductive solution to form a volatilizable organic photoconductive layer. The conductive layer, comprising a quaternary ammonium polyelectrolyte and a surfactant, provides an electrode for the photoconductive layer and has improved electrical and physical properties compared to prior conductive layers.

Abstract: Error concealment apparatus for correcting errors in signals representing video images includes means for detecting image gradients in an area surrounding a lost block of image data. Circuitry responsive to these image gradients generates a plurality of blocks of directionally interpolated pixel values. The pixel values in the respective blocks of directionally interpolated pixel values are sorted according to amplitude, and then pixel values from mutually exclusive positions in the respective blocks are selected to form a block of pixel values for error concealment.

Abstract: A system for processing a high definition television signal includes a codeword prioritizer responsive to a codeword datastream derived from an MPEG-like encoder. The prioritizer generates a flag to indicate a breakpoint between high priority and standard priority codewords within a given image data group. Null codewords are inserted into the codeword datastream during intervals when the prioritizer is analyzing codewords to determine where to establish the priority breakpoint. The null codewords are ignored by a following transport processor which packs codewords into cells.

Abstract: A differential comparator includes first and second transistors for comparing an input signal to a reference signal during a comparison phase and circuitry for balancing the quiescent currents through the transistors. The circuitry includes a first current source connected to the source of the first transistor, a second current source connected to the source of the second transistor and a selectively enabled impedance means connected between the sources of the two transistors. Prior to each comparison phase the currents through the first and second transistors are balanced (i.e. made approximately equal) by application of equal voltages to the gates of the two transistors and cross-coupling the source potentials of the first and second transistors to control the second and first current sources.

Abstract: A pulse-width modulator controls a switching transistor. The switching transistor is coupled to a primary winding of a chopper transformer. The switching transistor and the primary winding are referenced to a nonisolated ground conductor. To initiate a standby mode of operation, a first on/off control signal that is referenced to an isolated ground conductor disables a horizontal oscillator that is energized from a secondary winding of the chopper transformer and that is also referenced to the isolated ground conductor. As a result, a decrease loading of circuit elements that are referenced to the isolated ground occurs. In the standby mode, current pulses in the primary winding are produced at a substantially higher frequency than in normal operation. A frequency detector referenced to the nonisolated ground generates a second on/off control signal that is referenced to the nonisolated ground in accordance with the frequency of the current pulses in the chopper transformer.