Abstract: A deflection apparatus includes a pair of quadrupole arrangements for producing a pair of quadrupole fields in a beam path of an electron beam at different distances from a display screen. In an embodiment of the invention, the first and second quadrupole arrangements and a main deflection field producing arrangement cooperate to converge three electron beams, R, G and B, with one another.

Abstract: An improved cathode-ray tube includes a viewing screen and an electron gun for generating and directing three electron beams toward the screen. The gun includes at least eight electrodes spaced in order from three cathodes, with the furthest electrode from the cathodes being interconnected to a tube anode. The electrodes form a beam forming region, a first quadrupole lens, a main focus lens and a second quadrupole lens in the path of each electron beam. In the improvement, the second quadrupole lens is positioned on the anode side of main focus lens, with the first quadrupole lens being diverging for defocusing the beams, and the second quadrupole lens being converging for focusing the beams in the horizontal plane.

Abstract: A high voltage, inverting, kinescope driver amplifier is coupled at the input thereof to a source of low voltage video input signals to be amplified and is coupled at the output thereof for supplying amplified video output signals to the cathode of a kinescope. The high voltage amplifier includes linear and non-linear feedback paths which, in combination, determine a nominal closed loop gain for the amplifier. The non-linear path includes amplitude and frequency dependent elements for increasing the closed loop gain of the amplifier by a given amount in low brightness areas (black to gray) displayed by the kinescope (thus improving dark picture detail) and increases the closed loop gain of the amplifier by substantially the same given amount for high frequency video detail signal components in high brightness picture areas (thus improving subjective contrast without spot blooming and avoiding the impression of "washed-out" pictures.

Abstract: A film/video detector includes circuitry for generating the differences between corresponding pixel values in successive frames of video signal. These differences are accumulated over respective frame intervals. Accumulated values for respective frames are applied to a signal averager and to a correlation circuit. Average values from the averager are subtracted from correlation values from the correlation circuit, and film mode signal is indicated if the latter differences are greater than a predetermined value.

Abstract: A television receiver responds to a quadrature amplitude modulated (QAM) signal containing symbols mapped into a four quadrant grid-like constellation defined by I and Q axes. Demodulated I and Q components are processed by a carrier recovery network which adjusts the parameters of a locally generated carrier reference signal so as to maintain a desired orientation of the QAM constellation. The carrier recovery network includes a time multiplexed processor, including a signal multiplier, exhibiting plural operating modes in a digital phase locked loop exhibiting a loop delay of one symbol period.

Abstract: An automatic beam current limiting arrangement of a television receiver or display monitor comprises an average beam current limiter coupled to the low side of the high voltage transformer for reducing the contrast of a reproduced image when the average beam current exceeds a threshold and a peak current limiter coupled to the cathodes of the picture tube for controlling a current source which determines the threshold of the average beam current limiter in response to the sum of the cathode currents of the picture tube. In one embodiment, the cathode current sensing circuits comprise the same cathode current sensing circuits utilized in an automatic black level setting arrangement. This beam limiting arrangement allows operation at high contrast levels while inhibiting excessive peak white areas.

Abstract: A transition enhancing circuit includes a tapped delay line which provides successively delayed replicas of the signal to be processed. A multiplexer, responsive to a signal transition, sequentially couples delayed signal from the center tap and taps more distant from the input of the delay line to an output terminal to effectively hold the initial value of the transition for approximately half the transition period. The taps at the input end of the delay line up to and including the center tap are then sequentially coupled to the output terminal to effectively advance, in time, the end value of the signal transition. The signal transition is thereby reduced to a time equivalent to the switching interval between taps.

Abstract: A selectable aspect ratio raster is generated on a CRT with a 16:9 aspect ratio screen by a deflection yoke and deflection amplifier. The deflection amplifier is coupled in a non-floating configuration to the deflection yoke. This permits a switching arrangement to control the horizontal deflection amplitude by the selectable addition of inductance in series, with the yoke. The switching arrangement also controls other deflection circuit parameters to provide optimum raster correction at the selected aspect ratio.

Abstract: Apparatus for detecting the presence of a pseudorandom number (PRN) sequence used in a television receiver for reducing multipath interference such as image ghosts includes a multiplier responsive to a video signal containing the PRN sequence test signal component, and to a delayed version of such video signal. The amount of the delay is related to the duration of a PRN sequence, and one of the multiplier inputs is substantially devoid of average and DC components. A multiplier output representing correlation of the input signals indicates the presence of the test signal component, which is then passed to a network for processing to develop coefficients for a deghosting filter.

Abstract: First circuit apparatus, comprising a given number of prior-art image-pyramid stages, together with second circuit apparatus, comprising the same given number of novel motion-vector stages, perform cost-effective hierarchical motion analysis (HMA) in real time, with minimum system processing delay and/or employing minimum hardware structure. Specifically, the first and second circuit apparatus, in response to relatively high-resolution image data from an ongoing input series of successive given pixel-density image-data frames that occur at a relatively high frame rate (e.g., 30 frames per second), derives, after a certain processing-system delay, an ongoing output series of successive given pixel-density vector-data frames that occur at the same given frame rate. Each vector-data frame is indicative of image motion occurring between each pair of successive image frames.

Abstract: A high definition television receiver including analog and digital signal processing circuits receives an analog high definition television signal representative of digital television information. The received signal contains narrowband high priority information and wideband low priority information. An automatic gain control (AGC) signal is developed from the narrowband information as a function of the values of coefficients of an associated adaptive equalizer, and as a function of the number of saturated samples processed by associated input analog-to-digital converters.

Abstract: In a television receiver, an ultor accelerating potential or high voltage for a picture tube is derived by rectifying a retrace pulse voltage developed in a high voltage winding of a flyback transformer. The retrace pulse voltage is developed by a horizontal deflection circuit output stage that is coupled to the high voltage winding via a primary winding of the flyback transformer. The horizontal deflection circuit output stage includes a horizontal deflection winding, a retrace capacitor and a trace switch. The trace switch includes a damper diode and a horizontal output transistor. An energy storage coil is coupled in parallel with a third winding of the flyback transformer during a controllable time interval beginning during the second half of horizontal trace and ending during retrace. The energy stored in the coil during the trace portion is transferred to the flyback transformer during retrace to enhance high voltage at high beam currents.

Abstract: A receiver for receiving block coded HDTV compressed digital video signals decimates the data in each block to produce NTSC resolution images but with a significant savings in receiver hardware.

Abstract: A processing system requiring adaptive selection of ones of a family of transfer functions is implemented with a single transfer function element arranged to perform a transfer function representative of the family of functions. Respective ones of the family of transfer functions are realized by selectively offsetting signal applied to the transfer function element, and selectively offsetting and scaling signal provided by the transfer function element.

Abstract: An impulse noise detector for detecting impulse noise in video signal includes a band pass filter for passing a band of video signal frequencies centered in the spectral region of video signals which exhibit a relative energy minimum. The band pass filtered signal is applied to a vertical comb filter. A threshold detector is coupled to the output connection of the comb filter for detecting the occurrences of impulse noise.

Abstract: A television signal to be equalized to compensate for transmission channel frequency and phase irregularities includes a test signal. A difference signal representing the difference between the average (DC) value of the test signal and a DC reference component of the television signal is obtained, and a predetermined portion of the test signal is FFT transformed. A ratio of a desired DC difference to the obtained DC difference as represented by the difference signal is developed. A ratio of a desired frequency response to a frequency response indicated by FFT transformed values, excluding DC, also is developed. Values associated with the two ratios are inverse FFT transformed, and the transformed values are used to control the parameters of an FIR filter for equalizing the television signal.

Abstract: In a cable television system an interferer signal is inserted into the video signal for scrambling purposes except during a vertical blanking reference interval containing a reference signal for use by a video equalizer in a television receiver to help reduce multipath distortion such as image ghosts.

Abstract: Image reproduction is improved in an MPEG-like television receiver by inclusion of post-processing adaptive error concealment. Compressed video signal is examined to determine blocks of video signal containing errors, and error tokens are generated for identifying corresponding blocks of decompressed pixel values. Pixel values adjacent the decompressed blocks of pixel values containing errors are examined to generate estimates of the relative image motion and image detail in the area of such blocks. The block of pixel values is replaced with temporally displaced co-located blocks of pixel values or interpolated data depending upon whether the estimate of image motion is lesser or greater than the estimate of image detail.

Abstract: A television receiver processes a television signal representing a letterbox image display format with an image region, and a bar region containing "helper" information to help convert from interlaced to progressive scanning. An image signal processing path contains a motion detector and switch for determining whether a video processor receives image information (in the presence of motion), or field repeated information (in the absence of motion). Another motion detector associated with helper signal processing exhibits a narrower motion spreading characteristic than the motion detector in the image path, and determines when the helper signal is coupled to the image path.

Abstract: A television signal receiver processes a television signal representing a letterbox image display format with a main image region, and a bar region containing auxiliary "helper" information to help convert from interlaced to progressive scanning. In the presence of image motion, a main image component and the helper component are combined and conveyed to a video processor. In the absence of motion, other image information, e.g., field repeated information, is conveyed to the video processor. The information conveyed to the video processor is determined by a switching network responsive to an control signal from a motion detector which senses low frequency luminance image information substantially exclusive of high frequency image information.