Abstract: Video signal processing apparatus includes a picture enhancement processor for processing a video signal to produce an enhanced video signal. The video signal includes a signal component representing video image data and another signal component representing non-image data such as vertical sync and a binary information component. The binary information component represents binary information that may occur, for example, during vertical blanking such as closed caption data, content advisory information (V-chip), or extended data services information. A control unit modifies the enhancement performed by the picture enhancement processor during intervals of the video signal that include non-image information. Modifying enhancement processing (e.g., reducing or disabling) during intervals that include the non-image information reduces degradation of the non-image information caused by the enhancement processing.

Abstract: A CRT 10 has an evacuated envelope 11 comprising a funnel 15 having a neck 14 and an open end. The funnel 15 is sealed at the open end to a faceplate panel 12 having a luminescent screen 22 formed on a viewing area of an interior surface of the faceplate panel by an electrophotographic screening process. The screen 22 comprises a multiplicity of different color-emitting phosphor elements. A light absorbing matrix 23 has a first portion that includes a multiplicity of openings therein overlying the viewing area of the faceplate panel, and a second portion providing an imperforate border 123 extending beyond the viewing area. The phosphor elements are disposed within the openings in the matrix. A color selection electrode 25 is mounted within the faceplate panel 12, in proximity to the screen 22. An electron gun 26 is centrally disposed within the neck 14 for generating and directing a plurality of electron beams 28 toward the screen 22.

Abstract: Video signal processing apparatus provides for blanking main and auxiliary images in a multi-image display, e.g., a PIP or POP display, independently. The blanking may be part of a V-chip feature in which blanking occurs in response to auxiliary information, such as XDS data, that is included in a video signal to indicate the content of television programming. Main image blanking occurs only during active video intervals to prevent corrupting sync information. In a system that produces the main image from various types of video signals, e.g., composite video and s-video, that require separate signal processing paths, main image blanking capability is provided in one signal path only, such as the composite video path. The blanking capability is activated and the associated signal path is selected to provide main picture blanking regardless of which type of signal is providing the main picture.

Abstract: A symbol timing recovery (STR) error detector includes a complex multiplier and a Gardner-type symbol timing error estimator for operation with carrierless amplitude phase (CAP) signals. Quadrature Ir and Qr signals from the system are input to the complex multiplier, which also receives signals from a numerically controlled oscillator operating at the CAP center frequency. The output of the complex multiplier is provided to the input of the Gardner STR error estimator. An added frequency shift allows the Gardner error estimator to function with CAP signals. The output from the error estimator is provided to a loop filter the output of which is provided to an oscillator which generates the symbol timing information for a symbol sampling network.

Abstract: A current picture partitioned into a plurality of partitions is received and encoded by determining a total target number of encoded bits for the current picture to avoid overflow or underflow of a video buffer verifier (VBV) maintained by an encoder. The encoder determines a local target number of encoded bits for each partition of the current picture, in accordance with the total target number. A plurality of partition encoders encode each partition, respectively, in accordance with the local target number for said each partition, wherein each partition encoder maintains a local VBV having a local VBV fullness, to monitor local underflow or overflow conditions.

Abstract: A stereophonic audio processing system having left and right stereophonic sound channels with respective loudspeakers therefor is presented. The system is provided with spatial expansion of the stereophonic sound so that a first pair of spaced-apart loudspeakers will acoustically appear to be spaced further apart then they actually are. The audio system is provided with provisions for connecting a second pair of loudspeakers which can be spatially located at a distance between the loudspeakers which is larger than the first pair of loudspeakers. The audio system is provided with apparatus for providing stereo sound without spatial expansion when such secondary loudspeakers are used.

Abstract: A high-voltage power supply of a video display apparatus provides an ultor voltage and a focus voltage to a cathode ray tube. A low-voltage power supply provides a variable voltage to a primary winding of a flyback transformer of the high-voltage power supply. The magnitude of the variable voltage is responsive to first and second feedback signals provided by first and second negative feedback paths. The first feedback signal is derived from the ultor voltage and is used to regulate the ultor voltage. The second feedback signal is provided by the low-voltage power supply via a path that bypasses the high-voltage power supply, and is summed with the first feedback signal to ensure that the focus voltage remains at or above a predetermined minimum voltage.

Abstract: A system and method for altering the appearance of interference in a video signal caused by spurious interference generated by repeated high speed digital memory write operations affecting video processing in analog circuitry in thereceiver. In one particular embodiment, a picture-in-picture television receiver is provided wherein both the main and sub-pictures are processed on a single IC including analog processing circuitry, as well as a small picture memory array to which small picture video samples are repeatedly being written. The visibility of spurious interference in the picture is reduced by periodically altering the clock timing during the repetitive high speed writing operation to redistribute the interference so as to be less noticeable to the television viewer.

Abstract: A kinescope video driver includes a series connection of a main cascode transistor coupled to a cathode of a cathode ray tube and a video signal amplifying transistor. A second cascode transistor is coupled between the main cascode transistor and the video signal amplifying transistor. The second transistor is coupled to the video signal amplifying transistor through a short wire conductor and to the main cascode transistor through a long wire conductor.

Abstract: A digital television system which processes television information in the form of a stream data packets representing video and audio information in compressed form, such as MPEG, includes on-screen display (OSD) provisions for displaying sophisticated graphics, such as animation, by storing graphics data in a read only memory (ROM) in the same compressed form as that used for the video information. The graphics data is transported to the same video decoding and decompression unit which processes the video data contained in the video packets to form digital signals representing video information in uncompressed form, where it is converted in the same manner as the video data to form graphic image data. A multiplexing arrangement is provided so that digital signals representing animation graphics can be multiplexed with digital signals representing static graphics image data derived from bit-mapped representations.

Abstract: Apparatus and method for receiving a QAM signal using a backward compatible hierarchical coding scheme to increase data transmission using finer constellations, while maintaining compatibility with existing Direct Broadcasting Satellite (DBS) systems. The apparatus employs multiple stages of decoders such that the finer constellations of the QAM signal are unraveled at different stages.

Abstract: A system and method for receiving and rendering Unicode text in multiple languages on a set top box is disclosed. The system includes a set top box which receives an application program from a broadcast station. The set top box executes the application program. The application program includes Unicode character encoding text for display on a television coupled to the set top box. An operating environment running on the set top box includes a Unicode encoding engine which the application program invokes to display Unicode text. The encoding engine determines the language of characters in the text and invokes a rendering engine corresponding to the language of each character, thus enabling characters from different languages to be mixed in the same text string. The rendering engine has specific knowledge of the language, such as rendering direction and context.

Abstract: A delay correction circuit includes a source of a clock signal and a source of a timing signal asynchronous with the clock signal. A timing signal detector is responsive to the clock signal and the timing signal, and is properly operative only when the timing signal is stable for a predetermined time period around the clock signal. A control circuit conditions utilization circuitry to operate after a delay time after the timing signal is detected. Adjusting circuitry conditions the control circuit to adjust the delay time if the timing signal was not stable within the predetermined time period.

Abstract: A video signal processing system produces an output signal suitable for producing a closed caption display and is responsive to a "freeze" command from a user for modifying generation of the output signal such that the content of the closed caption region of the display does not change. The system provides for user selection of various freeze modes including one in which just the caption region of a display is frozen, another in which just the video region of the display is frozen, and another in which both the caption and video regions of the display are frozen.

Abstract: A controller for a switch mode power supply includes an undervoltage protection circuit responsive to an input supply voltage indicative signal. The input supply voltage indicative signal is also coupled to a foldback point correction circuit. The correction circuit causes a decrease in a maximum duty cycle of a control signal when the input supply voltage increases and is still smaller than a predetermined magnitude. A zener diode limits the input supply voltage indicative signal in a manner to prevent a further decrease in the duty cycle when the input supply voltage exceeds the predetermined magnitude.

Abstract: Run/standby switching including switching to standby upon excessive current loading are provided in a switched mode power supply useful as an auxiliary power supply in a television. A switching controller IC is coupled between a primary transformer winding on the rectified raw B.sup.+ input voltage and ground. A switching transistor is coupled to the control input of the controller and is biased by the raw B.sup.+ input voltage for pulling down the control input. A run/standby control circuit and an overcurrent protective circuit disable the switching transistor during run mode operation and enable the switching transistor upon an overcurrent fault. The switched-mode power supply is further provided with a quick-reset capability to enable the power supply to consistently provide output voltages which are within nominal output voltage levels despite rapidly repeated dislocations in the operational mode of the apparatus.