Abstract: A pix-in-pix television display, with a digital memory for holding samples representing one field of the small picture, includes circuitry for converting eight-bit luminance samples into five-bit samples for efficient storage in the digital memory. A subtracter subtracts a predetermined block level bias value from each sample and an adder adds a two bit psuedo-random dither value to each sample. The six most significant bits of these samples are applied to a limiter which changes the samples having values greater than thirty-one to have values of thirty-one. The five-bit luminance samples are obtained by taking the five least significant bits of the samples provided by the limiter.

Abstract: Arc-over in the cathode ray tube of a digital television receiver produces a large current pulse which, when it discharges via the chassis ground, disrupts the reference ground potentials of other circuitry coupled to the chassis ground. The affected circuitry includes digital data storage elements which may experience random state changes caused by the fluctuating ground potential. The CRT arc-over condition is detected by circuitry which applies a pulse to the reset terminal of the microprocessor, causing it to restore the potentially corrupted data in the data storage elements using preset data stored in a less volatile programmable read only memory.

Abstract: A video signal recursive filter includes circuitry for controlling the integration time of the filter. The control circuitry develop a motion-threshold value responsive to the noise content of signal differences developed by subtracting a processed signal, delayed by a frame period, from an incoming video signal. The signal differences are compared against the motion threshold to develop motion signals indicating the history of image motion for each picture element. Circuitry responsive to the signal noise content develops a signal which is coupled to the motion signals to form address codewords that are applied to a ROM programmed with predetermined control signals for establishing the integration time of the recursive filter.

Abstract: A pix-in-pix display includes a filtering system for processing the video signals which produce the reduced-size image. The filtering system includes an anti-aliasing filter which reduces the amplitude of the components of the video signals which may cause aliasing distortion when the image is subsampled. However, the filter passes substantial amounts of these components. The filtered video signal is subsampled and applied to a peaking filter which amplifies the band of frequencies containing the aliasing components relative to lower frequency bands to improve the appearance of detailed portions of the reproduced image.

Abstract: A video monitor includes apparatus for generating a horizontal blanking pulse accurately timed with respect to a horizontal image retrace interval. The leading edge of the blanking pulse is derived from a differentiated horizontal oscillator signal which is applied to one input of a gate having a threshold operating level. The lagging edge of the blanking pulse is generated when the amplitude of a horizontal flyback pulse applied to another input of the gate falls below the gate threshold level.

Abstract: A digital television receiver, which uses a comb filter to separate the luminance and chrominance components of composite video signals, includes an adaptive band-pass filter for processing the comb filtered chrominance signals. Comb filtered chrominance signals may include luminance vertical detail information at the relatively high frequencies also occupied by chrominance information. The adaptive band-pass filter is controlled to have a narrow bandwidth when significant amounts of this relatively high frequency vertical detail information are present and to have a wide bandwidth otherwise. Consequently, the bandwidth of the chrominance signal provided by this filter is restricted only when it is necessary to prevent distortion, and vertical detail is added to the luminance signal only when it is not likely to be contaminated with chrominance information.

Abstract: A digital deghosting system uses the interval between the sixth pre-equalization pulse and the first serration as a training signal to determine the timing and amplitude of ghost signals relative to the desired signal. The system includes level shifting circuitry to change the amplitude of the video signals during the training interval. This amplitude shift ensures that all of the information concerning the ghost signals is within the dynamic range of the analog to digital converter.

Abstract: A motion detector for detecting interimage motion represented by composite video signals analyzes both the chrominance and luminance components for image motion. Interimage motion represented by the luminance component is determined from interimage signal differences. The interimage signal differences are separated into high and low frequency spectra corresponding to fine and coarse luminance image detail. Selected signal differences from the low frequency spectrum are summed and threshold detected to determine motion in the coarse image detail. The high frequency spectrum of the sample differences are applied to parallel summing circuits which sum different combinations of sample differences in order to discriminate motion signals from non-moving chrominance transitions. The detection signals from the high and low frequency motion detectors are combined to produce a luminance motion signal.

Abstract: A narrow bandwidth analog-to-digital conversion (ADC) system is described in the context of the color burst processing and burst phase detecting circuitry of a digital color television receiver. The ADC includes a dither generator which adds a dither signal to either the analog input signal or to the reference signal used by the ADC. This dither signal increases in magnitude by 1/16 of an LSB value at a rate one-quarter of the burst frequency and changes in sign at one-half of the burst frequency. This signal passes through a low-pass filter in the chrominance channel providing an increase in sample resolution by averaging the samples in a chroma band-pass filter and in the phase detecting circuitry.

Abstract: A motion adaptive recursive filter is modified to separate luminance or chrominance signal from composite video. The filter proportions and sums current and frame delayed signal recursively to provide signal-to-noise enhanced luminance signal with the chrominance component reduced to a steady state residual value the first frame after motion ceases. Current composite video signal is appropriately scaled and combined with the signal-to-noise enhanced signal to cancel the residual chrominance component therein.

Abstract: A television receiver responsive to broadcast television signals in a normal operating mode includes a video channel with high frequency peaking circuits, followed by a wideband display driver to which auxiliary R, G, B color image signals are applied in an auxiliary operating mode of the receiver. A low pass filter restricts the high frequency response of the video channel in the normal mode so that the combination of the high frequency peaking circuits and the wideband display driver does not result in a condition of excessive signal bandwidth and attendant unwanted spurious high frequency signal effects.

Abstract: In a video monitor for display alphanumeric data on a kinescope display screen, a kinescope driver transistor receives binary video data signals at a low impedance emitter input electrode and provides high level video data output signals to the kinescope from a collector output electrode. A source of adjustable control voltage is coupled to the base electrode of the driver transistor for varying the intensity of the data display.

Abstract: An input filter for coupling television signals from a signal source such as an antenna to an RF signal processing stage includes series resonant input and output sections shunting the signal path. The input section forms a trap at the video IF frequency. The output section resonates at a frequency other than the sound IF frequency, below the band of television signal frequencies to be processed by the RF signal processing stage. The filter serves to attenuate unwanted stray signals such as video and sound IF components otherwise capable of interfering with and distorting the input television signals.

Abstract: In a video signal processing and display system such as a television receiver employing digital video signal processing techniques, viewer generated control signals for normally controlling the brightness and/or contrast of a displayed image are utilized in analog rather than digital form for controlling the magnitude of the video signal.

Abstract: A television receiver includes a kinescope and a current sensing transistor for conveying amplified video signals to the kinescope, and for providing at a sensing output terminal an output signal related to the magnitude of kinescope current conducted during given sensing intervals. A clamping circuit clamps the sensing output terminal during normal image intervals, and unclamps the sensing output terminal during the sensing intervals. The clamping circuit facilitates interfacing the sensing transistor with utilization circuits which process the sensed output signal, and assists to maintain a proper operating condition for the sensing transistor.

Abstract: A receiver includes a line store progressive scan processor and a frame store progressive scan processor for doubling the line rate of a video input signal for display. The video input signal includes an identifying signal signifying whether the fields that are derived from a common scene. The identifying signal is detected and used to control a switch for selectively coupling the output of the processors to a display such that frame store processed signals are displayed for fields derived from exactly the same scene and line store processed signals are displayed for "mixed" fields (i.e., fields from different frames or frames containing motion).

Abstract: A motion detector for detecting motion in a picture contained in a television signal includes a filter that extracts a portion of the frequency spectrum of the television signal. The amplitude of the sidebands of the television signal in this portion of the frequency spectrum is indicative of motion in the picture scene. The signal from the filter is coupled to a peak detector that produces a motion indicative signal. The amplitude of the motion signal is proportional to the absolute value of the amplitude of the sidebands in this portion of the spectrum.

Abstract: In a digital video signal processing system including a kinescope for displaying a video image, a video signal digital-to-analog converter receives input digital video signals and provides high level output analog video signals with a magnitude suitable for directly driving an intensity control electrode (e.g., cathode) of the kinescope.

Abstract: An IF signal filter in the IF sound channel of a television receiver exhibits peak amplitude responses which are unsymmetrical and slightly offset from the nominal picture and sound carrier frequencies by an amount dictated by the amount of tilt introduced by the tuner and the IF signal processing section. As a result, a filtered IF signal applied to a sound demodulating system exhibits a substantially symmetrical characteristic with respect to both the sound and picture carrier frequencies, yielding reduced audio buzz and harmonic distortion.

Abstract: A recursive filter for effecting noise reduction of video signals, sums current and delayed signals and includes a motion detector for detecting interframe image motion. Signal from the motion detector is stored to provide a history of image motion. A decoder coupled to the motion detector and also responsive to the stored motion history develops control sequences for scaling the signal contributions which form the recursive filter sums.