Abstract: A BICMOS voltage controllable delay element has an input terminal that is supplied with an input voltage from a pair of BICMOS transmission gates. The input voltage is either a control voltage or a reference voltage as determined by the state of an input signal. A first BICMOS inverter is switched by the input voltage and the charge and discharge of a timing capacitor is controlled by the magnitude of the control voltage and the reference voltage. A second BICMOS inverter responds to the timing capacitor voltage for developing an output signal voltage that is phase delayed with respect to the input signal voltage. A precision delay element using a PLL circuit is shown as are a frequency multiplier arrangement and a pulse width measuring arrangement.

Abstract: A precoded N-level HDTV digital video characterized by a sampling rate fs substantially equal to 3/2 the NTSC color subcarrier frequency is modulated for transmission on a carrier signal having a frequency substantially mid-way between the picture carrier and color subcarrier of an NTSC co-channel. The received signal is detected by a synchronous detector in response to a regenerated carrier signal and interfering NTSC beat components in the output of the detector are attenuated by a comb filter having a notch at fs/3. The output of the comb filter comprises an M-level signal, where M is greater than N, which is converted to an N-level signal corresponding to the demodulated video signal.

Abstract: NTSC co-channel interference is reduced in an HDTV receiver by developing an interference signal that is representative of the high energy components in the NTSC signal and subtracting the interference signal from the received HDTV signal to produce an enhanced HDTV signal for processing.

Abstract: A static phase error responsive oscillator control includes a phase detector coupled to a source of horizontal synchronizing pulses, a low pass filter, an error amplifier, a voltage controlled oscillator having a frequency equal to a multiple of the horizontal scan frequency, and a corresponding frequency divider. A threshold detector responds to error signals in excess of predetermined upper and lower thresholds to indicate large magnitude frequency corrections. An averaging circuit determines the long term character of the large magnitude corrections to alter the free-running or static frequency of the oscillator. Once the free-running frequency is corrected, static phase error is substantially reduced or eliminated.

Abstract: A balanced A/D converter system for a video signal. A clamp reference, corresponding to synchronizing pulse magnitude, is developed. The output of an A/D converter is summed with the clamp reference to develop a first correction signal for offsetting the video signal to the synchronizing pulse back porch level at the input of the A/D converter. A peak video reference signal is developed and summed with the output of the A/D converter to develop a second correction signal for controlling the gain of a variable gain amplifier coupled to the input of the A/D converter. Offsetting the video signal to the back porch level and amplifying the video signal based upon its maximum level enables the full utilization of the total range of the A/D converter.

Abstract: A system and method for ultrasonic cleaning of an in-process shadow mask contaminated with polymeric films such as are employed in color cathode ray tube (CRTs) screen production. The ultrasonic bath contains a solution having a chemically active agent for degrading and removing a targeted cross-linked polymer film contaminant from the shadow mask. The cleaning solution may also have more conventional materials in addition to the chemically active agent. The chemically active agent, attacks PVA films contaminating the mask, may be hydrogen peroxide or a periodate. The agents act to chemically degrade the polymeric contaminants. Contaminants are thus removed from the shadow mask during CRT production to reduce clogging of shadow mask apertures and facilitate attachment of the shadow mask to a faceplate-mounted support structure.

Abstract: A television transmission system includes a transmitter that transmits a digital video signal, including an error code, that is dispersed in one sense and a receiver having a selectively reversible complementary dispersal filter and an error detection circuit for recovering the transmitted signal. The error rate of the received signal is used to automatically select the correct sense of the receiver dispersal filter.

Abstract: A video image signal is transform coded to derive a plurality of blocks of transform coefficients, the coefficients of each block being separated into horizontal, vertical and diagonal spatially related regions. A plurality of values each representing the degree to which a portion of the video image is characterized by a respective image related perceptual characteristic are derived in responsee to the estimated energy in the three regions. The derived perceptual values are combined and weighted to provide a single output value corresponding to each coefficient block.

Abstract: A television system includes a plurality of complementary transmitter and receiver stages for processing an HDTV signal to minimize co-channel interference to and from NTSC signals, thereby facilitating the use of so-called "taboo" channels for the transmission of HDTV signals. The HDTV signals are encoded for transmission in a format exhibiting dominant periodicities equivalent to that of NTSC to further minimize such co-channel interference.

Abstract: A post-mask-deflection color cathode ray tube is disclosed that has a strip-type tension foil shadow mask in the form of two intercalated combs providing mutually insulated first and second arrays of strips. Each of the arrays is adapted to receive a different electrical potential effective to cause electron beams passing therethrough to be deflected by the electrical fields created between the strips. A method of manufacturing is also disclosed.

Abstract: A video signal comprising a successive series of frames is sub-band coded to derive a plurality of groups of coefficients for each frame. Each group of coefficients comprises a spectral representation of the video content of a respective portion of the frame, which portions are spatially decorrelated relative to the corresponding portions of the immediately preceding and immediately following frames to reduce block artifacts in the reproduced image.

Abstract: Apparatus for applying a conductive coating of DAG material to the inner surface of a cathode ray tube (CRT) funnel includes a stationary DAG spray gun and a movable DAG rotating slinger. The CRT funnel is rotated to allow the stationary spray gun to deposit a first DAG coating on an intermediate flared portion of the inner surface of the funnel, including the location of its anode button. The DAG slinger, which includes a rotating disc for radially discharging the DAG, is then displaced through the neck portion of the CRT funnel toward the open, enlarged end of the funnel to deposit a second DAG coating which overlaps the first DAG coating. The apparatus includes a variable DAG flow control arrangement for depositing a DAG coating of uniform thickness over the inner surface of the CRT funnel, as well as a DAG cleaning and recovery arrangement for preventing DAG not deposited on the CRT funnel from escaping to the environment and for recovering this DAG for re-use.

Abstract: A delay circuit includes an output voltage controllable BICMOS delay element that is coupled to a phase locked loop that develops a control voltage. The control voltage is applied to the output BICMOS delay element and to another BICMOS delay element in the phase locked loop. An input voltage is applied to the phase locked loop and, along with the output of the phase locked loop, to the output BICMOS delay element.

Abstract: A stereo television receiver includes a microprocessor for developing logic level control signals for controlling tuning, video processing and a LED stereo indicator. A sync separator circuit supplies a horizontal signal to a peak detector which supplies a logic level output signal to the microprocessor. An audio mute circuit includes a pair of transistor switches, one each coupled to the left and right audio channels. The switch base electrodes are coupled together and supplied through LEDs from two delay circuits. One delay circuit is activated by the LED stereo indicator logic level control signal and the other by a logic level output signal developed when a television signal is tuned. The period of the delay circuit activated by the tuning of a television signal is sufficiently long to permit a determination of whether a stereo or a monaural audio signal is present.

Abstract: A video signal transmission system includes a dispersal filter having a variable dispersal characteristic for time dispersing a video signal. The filter is supplied with dispersal coefficients from a ROM for continually varying its dispersal characteristic over each line of the video signal. The low frequency content of the video signal is removed and the resultant high frequency video signal is applied to the dispersal filter. The variably dispersed video signal is combined with data, including a coded representation of the low frequency portion and transmitted. A receiver receives the dispersed signal, removes the data and applies the dispersed signal to an inverse dispersal filter that is supplied with dispersal coefficients from a ROM for providing a complementary (inverse) time dispersal function for recovering the high frequency video signal. The data is decoded and the low frequency portion reconstituted and combined with the high frequency video signal.

Abstract: A junction box provides for interconnecting a plurality of sheathed, bare-end, high-voltage conductors for cathode ray tubes and the like. The junction box includes an enclosure, a plurality of spaced, parallel-arranged leaf-spring terminals mounted within the enclosure, and a like plurality of guides for guiding conductors into the enclosure and into contact with respective terminals. Ganged cams mounted on a slider provide for simultaneously locking a plurality of conductors in the enclosure against withdrawal by counter-deflecting the terminals against the conductors and prevent withdrawal from the enclosure. In addition to the quick connection of high-voltage conductors, the junction box provides for controlling the static and dynamic focusing of an electron gun.

Abstract: An anode connector assembly provides for connecting to a CRT anode cup a high-voltage conductor consisting of a metal wire covered by resilient insulation. The assembly comprises clamping means for clamping, against the resilience of the insulation, the insulation and a length of bare wire folded back over the insulation. The clamping means including means for making electrical and mechanical connection to the anode cup, whereby an electrical potential carried by the conductor is applied to the anode cup through the wire and the clamping means.

Abstract: A video system includes a scan converter for developing a progressively scanned display of video lines from a two field interlaced line system. A spatial array of six pixels covering two successive video lines is developed and gradients are determined between diagonally opposed pairs of pixels and a vertically opposed pair of pixels in the array. The interpolated pixel is developed by averaging the two pixels in the smallest of the gradients. A non-orthogonal display is developed by using horizontally interpolated pixels in the array developed by averaging successive pairs of real pixels, which introduces an offset of one-half pixel duration to the interpolated pixels. An adaptive peaking and noise coring circuit is included. Another spatial array of three line of pixels, both real and interpolated, is developed and a horizontal, a vertical and two diagonal gradients between pairs of pixels in the array are calculated.

Abstract: A CRT dynamic focus system, having independent corner adjustment, processes horizontal and vertical rate signals derived from the horizontal and vertical deflection systems of the CRT display. The composite horizontal output and vertical rate focus signals are supplemented by additional horizontal rate corner focus signals by separate top and bottom gated amplifiers. The phase and amplitude of the supplemental focus signals are independently adjustable.