Abstract: In an improved method of etching apertures in a thin metal sheet to form a shadow mask for a color picture tube, the metal sheet has a first acid-resistant stencil on one major surface thereof and a second acid-resistant stencil on the other major surface thereof. At least one of the stencils has openings therein at locations of intended apertures. The improvement comprises the steps of magnetically holding the metal sheet with a flat magnetic assembly, and moving the magnetic assembly magnetically holding the metal sheet thereon through an etching chamber. The magnetic assembly includes a magnetic layer that is supported on an acid-resistant board.

Abstract: A receiver system automatically adaptively tunes to broadcast signals that are variable in the number of channels that are transmitted, their signal coding type and their modulation format. A system receives a digital bitstream representing video information encoded in one of a plurality of different formats, and transmitted on one of a plurality of transmission channels. In the system, a method for acquiring data transmitted on a transmission channel involves selecting a transmission channel from the plurality of channels and selecting a modulation format. The method also involves tuning to receive the modulation format and determining whether valid data is being received on the selected transmission channel. The method steps are repeated until valid data is received. The method may also involve selecting a coding type, and tuning to receive the coding type.

Abstract: A programmable synchronizing system for selectively providing synchronizing signals at different rates, such as for incorporation in a video signal decompression system, includes an oscillator and a programmable counter. The programmable counter is conditioned to count pulses from the oscillator by alternate moduli in predetermined sequences to generate the synchronizing signals. The desired synchronization rate is effectively the average of the counter output resulting from counting by the alternate moduli.

Abstract: A method for compatibly tuning a video signal receiver to an image processing device involves generating a prompting message for display to prompt a user to initiate a command response. First and second signals are generated. Each signal incorporates the prompting message but only one of the signals is compatibly tuned to the display. The first and second signals are alternately provided to the display and the prompting message is legibly displayed when the compatibly tuned signal is provided. The signal that is compatibly tuned to the display is selected in response to the command.

Abstract: A method and apparatus for producing a wipe sequence on a display device from incoming compressed video bitstreams, accomplishes the wipe function processing entirely in the compressed domain of the compressed video bitstreams. The old and new video bitstreams or sequences separately undergo a 2-dimensional convolution between its decoded DCT coefficients and stored DCT coefficients of a particular known wipe function. Each convolved bitstream is buffered with its quantization scale and then summed with the other. The summed output bitstream is used by a multiplexer along with each bitstream's decoded macroblock data to provide a seamed output bitstream. A controller controls the process such as frame correlation for convolution and output multiplexing of the summed bitstreams.

Abstract: A method and apparatus for reformatting auxiliary information such as closed caption text that is extracted from a television signal. The apparatus reformats the text by removing redundant spaces, reorganizing the text to fit into an arbitrary sized closed caption window, converting any closed caption display mode (e.g., pop on, paint on or roll up) into a modified roll on display, and inserting speaker identifier prompts into the caption.

Abstract: An apparatus and concomitant method for constructing a valid OSD message bitstream from a plurality of stored character bitstreams. Each character of the OSD font set is initially scaled into a fixed block size, e.g., a block size of 16.times.16 pixels. Each character is then encoded into a "character bitstream" using the intra macroblock coding syntax. The character bitstream is stored within a storage medium. When a frame of OSD messages needs to be encoded, the character bitstreams are read from the storage medium and cascaded to form a valid OSD message bitstream which represents the frame of OSD messages.

Abstract: An electron beam tends to slope downwardly as it is deflected horizontally to form a raster in a video display apparatus. The sloping of the beam can cause geometric errors in the raster, for example orthogonality and parallelogram errors. A raster correction circuit substantially offsets the downward slope of the electron beam by modulating a vertical deflection current with an induced horizontal-rate raster correction current, thereby substantially eliminating orthogonality and parallelogram errors in the raster. In respective embodiments of an inventive arrangement taught herein, the horizontal-rate raster correction current is induced in the vertical deflection coils by magnetically coupling a filament pulse waveform, a horizontal deflection voltage waveform, or a horizontal deflection current into the vertical deflection coils.

Abstract: A projection television comprises a projection screen formed by a three dimensional hologram disposed on a film substrate. A projection tube has an optical path in a substantially orthogonal orientation with the screen and two other projection tubes have respective optical paths converging toward the first optical path at angles of incidence .alpha.. The hologram has a configuration effective for reducing color shift in the displayed images. The screen has a color shift less than or equal to approximately 5 for all angles .alpha., where 0.degree.<.alpha..ltoreq.30.degree., as determined by the maximum value obtained from at least one of the following expressions: ##EQU1## where .theta. is any angle within a range horizontal viewing angles, C(.theta.) is the color shift at angle .theta., red(.theta.) is the red luminance level at angle .theta., blue(.theta.) is the blue luminance level at angle .theta. and green(.theta.) is the green luminance level at angle .theta..

Abstract: A data transmission bus system is disclosed which includes a plurality of nodes coupled together by a ring bus. The ring bus transmits data in successive bus cycles, each bus cycle containing a plurality of bus words. One of the bus words in the bus cycle is a bus cycle synchronization word and the remainder of which are data words. The plurality of data words are allocated to a plurality of data channels.

Abstract: Apparatus and method for acquiring a program from a packetized signal in response to ancillary information included in the packetized signal. The packetized signal includes a plurality of program signals and ancillary information associated with the plurality of program signals. The apparatus includes means for identifying the ancillary information from the packetized signal, the ancillary information including master guide information for use in identifying and acquiring special guide information, and special guide information for use in acquiring program information associated with the plurality of program signals. The program signals may be acquired using identifier information that may be derived from the ancillary information. The apparatus includes means responsive to the ancillary information for acquiring a selected program from the packetized signal.

Abstract: A VCR includes apparatus for controlling a cable converter unit. In a preferred embodiment, infrared (IR) transmission of commands from the VCR to the cable converter unit is employed. An LED assembly holds the LEDs in a predetermined orientation and provides first and second IR ports through which different amounts of IR signals are transmitted.

Abstract: Apparatus for combining an auxiliary image and a main image includes a source of a main image signal and a source of samples representing an auxiliary image signal. A subsampler selectively subsamples the auxiliary image samples in either a quincunx subsampling pattern or a rectangular subsampling pattern. A signal combiner combines the main image signal and a signal representing the subsampled auxiliary image samples to generate a combined image signal. A control circuit generates a freeze control signal for the subsampler which conditions it to take samples in the rectangular subsampling pattern during a freeze frame operation, and in the quincunx sampling pattern otherwise.

Abstract: A radio frequency (RF) signal transmitter/receiver system comprises a pair of transmitter/receiver units. A microcomputer-based RF carrier detect system determines when an RF signal is present or absent. The RF carrier detect system is also responsive to noise interference signals at or near its currently-tuned receiving channel. In periods of inactivity, the RF signal receiver monitors its currently-tuned channel and upon detection of noise interference or upon a determination that the currently-tuned channel is occupied, initiates a fast scan operation to identify an unoccupied and relatively interference-free channel, and transmits a command to its paired transmitter/receiver unit causing it to tune to the newly-identified unoccupied channel.

Abstract: A field/frame conversion method for compressed digital video, especially MPEG type video, having mixed field/frame mode macroblocks in the DCT domain utilizes a 1-D IDCT/DCT approach rather than the conventional 2-D IDCT/DCT approach. A vertical 1-D IDCT is performed on the DCT domain mixed field/frame mode macroblock to obtain a horizontal 1-D DCT domain macroblock. Thereafter, field/frame conversion is performed on the horizontal 1-D DCT domain macroblock to yield a field or frame mode horizontal 1-D DCT domain macroblock, depending on the required conversion. Finally, a vertical 1-D DCT is performed on the field/frame converted horizontal 1-D DCT domain macroblock to yield a 2-D DCT domain macroblock.

Abstract: A light-absorbing matrix 23, having openings therein, is formed on an interior surface of a faceplate panel 12 of a cathode-ray tube 10 by providing a photoreceptor thereon, electrostatically charging the photoreceptor 72 to a substantially uniform level of charge, and exposing the photoreceptor to light through openings 33 in a color selection electrode 24 to selectively discharge the more intensely illuminated areas of the photoreceptor, without substantially discharging the less intensely illuminated areas. The photoreceptor 72 comprises a plurality of layers including a photoresist layer 56, a conductive layer 62, and a photoconductive layer 66. The openings 33 in the color selection electrode 24 have a dimension substantially greater than the dimension of the openings in the resultant matrix 23.The photoreceptor 72 is contacted with a liquid toner having charged pigment particles which form toner lines 84 on the less intensely illuminated areas of the photoreceptor.