Abstract: In a cathode ray tube, plural electron beams are directed towards a faceplate biased at screen potential and are magnetically scanned by a non-self-converging deflection yoke across the faceplate to impinge upon phosphors thereon to produce light depicting an image. The plural electron beams are substantially converged near two opposing edges of the faceplate. A processor changes the raster of the image from a first raster corresponding to position of the image to a second raster corresponding to the position of the plural electron beams on the faceplate. One or more electrodes between the tube neck and the faceplate are biased above and/or below screen potential to deflect electrons landing near the periphery of the faceplate.

Abstract: A command and control architecture for a compressed digital television broadcast studio. The architecture includes provisions for session management, real-time control of studio activities, the use of proxy objects to establish communications with objects not providing a high level of control, control of studio filter devices and stream management. The invention includes an object architecture particularly suited to a digital studio.

Abstract: A method and apparatus for distributing time and frequency information to a plurality of studios such that the studios can then use the time and frequency information frequency and timelock their studio components to the global reference. The apparatus includes various embodiments for facilitating the distribution of time and frequency depending upon the type of digital network that is used for distributing the television signals.

Abstract: A method and apparatus for distributing time and frequency information to a plurality of studios such that the studios can then use the time and frequency information frequency and timelock their studio components to the global reference. The apparatus includes various embodiments for facilitating the distribution of time and frequency depending upon the type of digital network that is used for distributing the television signals.

Abstract: In a cathode ray tube, plural electron beams are directed towards a faceplate biased at screen potential and are magnetically scanned by a non-self-converging deflection yoke across the faceplate to impinge upon phosphors thereon to produce light depicting an image. The plural electron beams are substantially converged near two opposing edges of the faceplate. A processor changes the raster of the image from a first raster corresponding to position of the image to a second raster corresponding to the position of the plural electron beams on the faceplate. One or more electrodes between the tube neck and the faceplate are biased above and/or below screen potential to deflect electrons landing near the periphery of the faceplate.

Abstract: A method and apparatus for splicing a first compressed digital information stream into a second compressed digital information stream. The first information stream includes at least one entrance indicium identifying an appropriate stream entrance point, the second information stream includes at least one exit indicium identifying an appropriate stream exit point. A controller monitors the two streams until the appropriate points are found and, in response to a control signal, splices the first stream into the second stream.

Abstract: A studio class directory structure, for example, in a computer-readable media. The directory structure has a gateway service interface as a root directory, a devices class directory, coupled to said root directory, a servers class directory, coupled to said root directory, a studios class directory, coupled to said root directory and a software resources class directory, coupled to said root directory.

Abstract: A preprocessor for conditioning interlace-scan video signals for frame based compression, includes apparatus to accept fields of interlace-scanned video and provide fields of interlace-scanned luminance and chrominance component signals. The fields of interlace-scanned luminance component are combined into respective frames of luminance signal and applied to compressor apparatus for further processing. The fields of interlace scanned chrominance components are independently processed at the field level to generate lines of chrominance values which are interstitial to the lines of the original chrominance values and at a lesser pixel and line density. The independently processed fields of interlace-scanned chrominance signals are combined into respective frames of chrominance component signals and applied to compressor circuitry for further processing. Performing the chrominance signal interpolation and subsampling at the field level tends to eliminate a majority of color distortions around moving images.

Abstract: Apparatus for encoding/decoding a HDTV signal for e.g., terrestrial transmission includes a compression circuit responsive to high definition video source signals for providing ierarchically layered codewords CW representing compressed video data and associated codewords T, defining the types of data represented by the codewords CW. A priority selection circuit, responsive to the codewords CW and T, parses the codewords CW into high and low priority codeword sequences wherein the high and low priority codeword sequences correspond to compressed video data of relatively greater and lesser importance to image reproduction respectively. A transport processor, responsive to the high and low priority codeword sequences, forms high and low priority transport blocks of high and low priority codewords respectively. Each transport block includes a header, codewords CW and error detection check bits. The respective transport blocks are applied to an forward error check circuit for applying additional error check data.

Abstract: A commercial message timer stores data indicative of a first tuned station in response to a channel change command and begins repeatedly timing a predetermined time period. Upon each expiration of the time period, the user is reminded that the commercial message on the first tuned station may be over. In this way a user can avoid a commercial message on a first channel by setting the timer and scanning through other channels, and yet be reminded to return (e.g. by use of a PC (previous-channel) key) to the first channel at the end of a time period substantially equal to that of a typical commercial message. In another embodiment employing a videocassette recorder (VCR) the commercial timer is activated upon pressing the PAUSE key of the VCR so that the user may avoid recording the commercial message on videotape.

Abstract: Digital computer data recorded in a spiral track on the surface of a disk using a laser recording head which moves radially across the disk as it revolves at a constant linear velocity. A system for controlling the disk velocity during the recording process includes a device for counting each convolution of the spiral and means for calculating the number of bits of information which should optimally be recorded in that convolution. A counter keeps track of the number of bits which are actually being recorded in that convolution. The calculated number of bits is compared with the number of bits actually recorded to produce a control signal for regulating the speed at which the disk revolves.

Abstract: A system capable of synthesizing multi-channel sound for a computer includes a sound generator for each audio channel. A circuit provides a programmable delay so that one generator produces sound in one channel that is delayed with respect to the sound in the other channel. Multiple generators may be provided in each channel with each such generator having an independently programmable delay circuit associated therewith.

Abstract: A microprocessor embodied in an integrated circuit has a clock signal generator comprising an inverter in the integrated circuit and a frequency determining network external to the integrated circuit connected to the inverter through terminals. The clock signal generator generates a clock signal which determines the frequency of the instruction cycles of the microprocessor. The operation of the microprocessor is synchronized with a television horizontal rate signal by programming it to generate a comparison signal each time a predetermined number of instruction cycles, selected so that the comparison signal has the same nominal frequency as the horizontal rate signal have occurred. The simple wired AND gate serves as coincidence detector for the horizontal rate signal and the comparison signal and generates a pulse error signal representing the phase and frequency deviations between its two input signals.

Abstract: In automatic fine tuning (AFT) apparatus in a superheterodyne receiver, the IF carrier is selectively filtered and is applied to a signal multiplier arrangement. An auxiliary heterodyning signal is also applied to the multiplier arrangement, so as to produce an offset signal having a frequency proportional to the frequency difference between the IF carrier and the heterodyning signal. The offset signal is applied to a microprocessor programmed to produce a control signal for controlling the local oscillator to reduce frequency deviation between the IF signal and a nominal IF frequency.

Abstract: A digital-to-analog converter suitable for use in a television tuning system for converting bits of a digital word to a corresponding tuning voltage includes a first digital-to-duty factor converter responsive to a group of the most significant bits of the digital word for generating a first incrementally variable duty factor pulse signal and a second digital-to-duty factor converter responsive to a group of the next most significant bits of the digital word for generating a second incrementally variable duty factor pulse signal. The amplitude of the first and second pulse signals are differentially weighted, e.g., by standard tolerance resistors (.+-.10%), such that the maximum average DC potential of the second signal is greater than a single increment of the average DC potential of the first signal. The weighted signals are combined and filtered by a lowpass filter which derives the tuning voltage. This deliberately results in non-monotonicity but without a significant reduction in resolution.

Abstract: Synchronization of a source of computer controlled video to a video disc player for interactive application is obtained by sensing when the computer vertical sync leads that of the player and gating out a number of computer clock pulses equaling one video line during a period of one or more video lines. Horizontal synchronization is disabled during the vertical acquisition mode and then is established by modulating the computer clock frequency with a line rate phase error signal obtained from both video sources thereby providing rapid synchronization within approximately two seconds under worst case conditions.

Abstract: A transparent touchbar or touchplate is supported at its edges by a plurality of push-button switches. A plurality of valid touchpoints exist; and the touching of each can be distinguished, though the number of touchpoints is larger than the number of pushbuttons. This is done by logically combining the responses to the push-button switch closures occasioned by the application of force to any one of the valid touchpoints.

Abstract: A set-top teletext converter decodes the chroma burst signal of a color television signal with the substantially same amplitude and phase as the burst in the television signal. The teletext signal along with its transparent mode signal are decoded. The decoded teletext signal is then re-encoded as a standard television signal using the decoded burst signal. When switching between the encoded teletext signal and the regular television signal under the control of the transparent mode signal, no color shift is present.

Abstract: The tuning control system of a double-conversion tuner includes a phase locked loop type of frequency synthesizer for controlling the frequency of a controllable oscillator comprising the first local oscillator of the double-conversion tuner according to the frequency deviation of the difference between the frequencies of the first and second local oscillators from a reference frequency in order to compensate for the drift of either one of the local oscillators. An up/down counter which counts in one sense in response to the first local oscillator signal and in the other sense in response to the other local oscillator signal is used to generate the frequency difference signal. Because the frequency of the first local oscillator is always greater from the frequency of the second local oscillator the up/down counter can be implemented in the form of a simple pulse swallower.

Abstract: A microprocessor or other digital logic circuit recurrently tests the logical switching state of an input port. Based upon the outcome of such testing, the logical switching state at an output port is switched to the state opposite that of the input port. The recurrent testing develops at the output port a rectangular wave voltage that switches between upper and lower voltage levels. A filter coupled between the two ports develops at the input port a voltage representative of the average value of the output port voltage. The recurrent testing of the logical switching state of the input port produces a negative feedback of the output port voltage to the input port. The negative feedback develops a pulse-width modulated voltage at the output port that has an average value that is a multiple of the logic threshold voltage level of the digital logic circuit.