Abstract: A scanning circuit which utilizes blanking pulses between flyback pulses in a display device includes a line blanking circuit which prevents the generation of spurious blanking pulses by ringing in the blanking pulses. The line blanking circuit includes a capacitor for storing a reference voltage. A comparator is responsive to the reference voltage and to the flyback pulses and provides the blanking pulses when the flyback pulses exceed the reference voltage. The comparator is prevented from resetting for a preselected time period after the falling edge of the blanking pulse and spurious blanking pulses can not be generated during the preselected time period.

Abstract: A fixed filter determines a lower portion of the amplitude characteristic of a chrominance signal sideband correction filter. A variable filter determines the upper portion of the amplitude characteristic. A control signal tunes the variable filter for providing a symmetrical response for video signals having balanced color sidebands and tunes the variable filter for providing an asymmetrical response for video signals having unbalanced sidebands.

Abstract: A network combines luminance and chrominance signals to provide a composite video signal wherein the chrominance signal is subjected to band pass filtering to reject low frequency noise and the luminance signal is subjected to filtering by a predetermined amount at the color subcarrier frequency to reject color dots. In a preferred implementation, the filter is realized with only one inductor and one capacitor thereby preventing displayed artifacts with the economic and reliability benefits of minimal parts count.

Abstract: An FM detector for demodulating frequency modulated signals includes an FM detector having an oscillator composed of a capacitor and a Schmitt Trigger. The oscillator is controlled by the input signal to the FM detector. The FM detector also includes a phase detector for mixing the input signal with an oscillator signal from the oscillator to provide an output signal. The frequency of the oscillator is set to the frequency of the input signal using components internal to the FM detector. A first switch is used to charge and discharge the capacitor in accordance with the state of the Schmitt Trigger. A second switch is used to set the frequency of the oscillator to the frequency of the input signal.

Abstract: Read column conductors and write column conductors of a memory array are addressed by respective triggerable sequential pulse generators which, upon receiving respective trigger pulses, provide respective read and write address pulses to respective column conductors of the array. Data to be stored is written in parallel to cells of the memory a column at a time at a rate determined by the write sequential pulse generator and is recovered a column at a time at a rate determined by the read sequential pulse generator. Advantageously, (1) the ratio of the read and write rates may be selected to provide time compression, time expansion or constant delay of video data; (2) additionally data may be written and read concurrently without bus contention and (3) addressing is simplified by a timed application of trigger pulses to the pulse generators whereby there is no need for application to the memory of binary addressing data.

Abstract: A television system comprises a first input terminal (20) for providing a composite video (CSCC) signal or a separated luminance (SCC) signal, and a second input terminal (15) for providing a separated chrominance (C) signal. A change-over switch (11) has a first input (a) coupled to the first input terminal (20) through a path including a color sub-carrier filter (9), a second input (b) coupled to the second input terminal (15) through a path not including the color sub-carrier filter (9), and an output (c) coupled to the input (d) of a color decoder (8). The change-over switch couples the input (d) of the color decoder (8) to the first input terminal (20) in a first position (a), and couples the input (d) of the color decoder (8) to the second input terminal (15) in a second position (b). A sub-carrier detector (CK) is coupled to the output (c) of the change-over switch (11) for detecting the presence or absence of a color sub-carrier.

Abstract: Baseband chrominace components are time division multiplexed and subjected to vertical and horizontal recursive filtering thereby providing color component noise reduction in which vertical streaking characteristic of the vertical recursive filtering is effectively visually cancelled by horizontal streaking characteristic of the horizontal recursive filter thereby providing the benefits of (1) noise reduced baseband chrominance components (2) with minimal visual artifacts, (3) without requiring duplication of filtering elements whereby (4) reliability is increased and with a minimimum of filtering elements and (5) costs are proportionately reducted.

Abstract: Two transistors are operated individually as emitter follower buffer amplifiers for R-Y and B-Y input signals and are operated together as an inverting summing matrix for deriving a G-Y output signal from the R-Y and B-Y input signals. All three output signals are "buffered" (i.e., provided by low impedance sources) and are subject to substantially equal delays. Advantageously, the circuit implementation requires only two transistors and three resistors to provide output signals which are (1) buffered, (2) matrixed and (3) delay compensated and which features improved reliability (due to reduced "parts count") and an economic implementation of the buffering, delay compensation and matrixing functions.

Abstract: Plural signal delays in a progressive scan system are provided by a field memory having double multiplexing within a video line to provide compacted data samples including interleaved pixels in a first time interval representing field and frame delayed pixel samples and compressed motion data in a second time interval representing frame motion delayed by a field interval. Advantageously, the double multiplexing avoids the need for multiple field delays which otherwise would be required for providing field delayed video, frame delayed video and field delayed motion signals in motion adaptive systems designed for accurate reproduction of small fast moving objects in a displayed image.

Abstract: A video switch combines a first video signal with a compressed second video signal for application to a display unit to provide "picture-in-picture" images in which the first video is displayed in a main picture area of the display and the compressed second video signal is displayed as an inset picture within the main picture area. A non-linear processor, connected between an output of the video switch and an input of the display unit, enhances selected features of the combined video signal displayed by the display unit. Circuit means are provided for controlling the non-linear processor so that non-linear processing is applied to displayed images only in the main picture area and not in the inset picture area.

Abstract: A composite video input signal is separated into luminance and chrominance components by a signal separation filter and the components are applied to a display processor having a video display device coupled thereto for providing displayed images. For enhancement of detail in dark and light areas of the displayed images, the luminance signal is coupled to the display processor via a non-linear luminance signal processor which provides additional amplification in the dark and light areas but tends also to degrade the signal to noise ratio in those areas. To avoid a loss of signal to noise ratio in the enhanced areas the receiver includes a by-pass circuit for by-passing high frequency components of the luminance signal around the non-linear luminance signal processor and a filter in the non-linear luminance signal processor for attenuating the high frequency components.

Abstract: A television receiver includes a high voltage kinescope driver amplifier having an input for receiving a video signal and a further input for receiving a character input signal from a low voltage character amplifier. When switching from a "run" mode to a "stand-by" mode, a control circuit generates a turn-off command signal for disabling the kinescope high voltage supply and concurrently initiating turn-off of the receiver deflection circuit at a controlled rate during a transition interval between the "run" and "standby" operating modes. The turn-off command is further applied during the transition interval to an input of the character amplifier so as to over-ride any character signal which may be present to drive the output of the character amplifier to a maximum brightness level which, in turn, over-rides any video signal applied to the high voltage amplifier.

Abstract: A progressive scan processor includes an input circuit which produces a video difference signal representative of a difference between a first low frequency component derived from a current line of a video input signal and a second low frequency component derived by motion adaptive processing from a selected previous line of the video input signal. A line-rate doubling output circuit combines a line of the double line-rate difference signal with every other line of the double line-rate input signal to form a progressively scanned output signal. Advantageously, the system exhibits the relatively high vertical resolution and motion artifact immunity characteristic of motion adaptive systems as well as substantially reduced system memory requirements characteristic of "dual band" processors and it provides "dual band" processing of high and low frequency video components without the need for complementary band splitting filters having special amplitude and phase response characteristics.

Abstract: A source responsive to a composite video input signal provides line and burst frequency related timing signals. A measuring circuit responsive to the timing signals provides measurement values which tend to repeat when the video input signal is of a given color television standard and tend to exhibit a pseudo-random distribution otherwise. A histogram processor provides a histogram of the measurements occurring within a given time interval and provides an output signal identifying standard and non-standard video input signal based on the histogram of the measurements.

Abstract: A signal processor responsive to a video input signal provides a first video output signal linearly related to the input signal and a second video output signal non-linearly related to the video input signal. A first combining circuit combines the first and second video output signals in predetermined proportions to provide a third video output signal having both linear and non-linear components. A second combining means combines the second and third video output signals in proportions determined by an average picture level (APL) representative control signal to provide a processed video output signal having enhanced contrast for all values of the average picture level of displayed images.

Abstract: A source of switched supply voltage is applied to a potential divider and coupled to an output terminal via a capacitor. An output tap of the potential divider is coupled to the output terminal via the conduction path of a grounded base transistor. In operation the transistor (1) operates in an inverted mode for initially charging the capacitor, (2) operates in either a normal or an inverted mode for regulating a grid bias voltage at said output terminal for grid current flow of either direction relative to the output terminal and (3) operates in an isolation mode upon removal of the switched supply voltage whereby the capacitor applies a negative grid cut-off bias to the output terminal, said transistor in said isolation mode preventing discharge of the capacitor thereby providing a grid cut-off bias at said output terminal having an extended cut-off time constant due to the lack of any discharge path for the capacitor other than leakage.

Abstract: An input filter separates a luminance input signal into a high frequency component that is noise reduced by coring and a low frequency component that is noise reduced by a frame recursive filter preceded by sub-sampling and followed by sample rate restoration by interpolation. An output circuit combines the noise reduced components to provide a processed output signal in which high frequency portions thereof are subjected to coring and low frequency portions thereof are subjected to recursive filtering. In a specific application the frame recursive filter provides a plurality of low frequency sub-sampled components which are combined with the processed output signal in a further output circuit to provide a noise reduced output signal of progressive scan form.

Abstract: An input filter separates a luminance input signal into a high frequency component that is noise reduced by coring and a low frequency component that is noise reduced by a frame recursive filter preceded by sub-sampling and followed by sample rate restoration by interpolation. An output circuit combines the noise reduced components to provide a processed output signal in which high frequency portions thereof are subjected to coring and low frequency portions thereof are subjected to recursive filtering. In a specific application the frame recursive filter provides a plurality of low frequency sub-sampled components which are combined with the processed output signal in a further output circuit to provide a noise reduced output signal of progressive scan form.

Abstract: A diode is connected at a first electrode thereof to a source of input signal to be switched via a capacitor and is connected at a second electrode thereof via an output circuit to an output terminal. A bias control circuit, coupled to the diode, provides a first operating mode in which the diode is forward biased for coupling the input signal to the output terminal via the output circuit and provides a second operating mode in which the first electrode of the diode is DC isolated so that the diode rectifies the AC component of the input signal and in so doing generates a reverse bias for self-biasing the diode to a non-conductive condition.

Abstract: A color television receiver includes a picture-in-picture processor and a variable filtering circuit for imparting a "slope type" filtering characteristic to the chrominance component of displayed signals when the main picture being displayed is from a tuner video source and for imparting a "hay-stack" type filtering characteristic to the chrominance component when the main picture picture being displayed is from an auxiliary video source thereby providing an effective reduction in the visibility of chrominance signal sideband amplitude errors when displaying picture-in-picture images from different types of sources.