Abstract: A thermometer-to-binary encoder includes a set of J input stage encoders E(1) through E(J) and an output encoder D, where J= 2.sup.K is an integer greater than 1. A set of digital input signals each representing a separate bit of a thermometer code T is grouped into J signal subsets representing further thermometer codes T(1) through T(J) providing inputs to a set of input stage encoders E(1) through E(J) respectively. Encoder E(J) produces an N-K+1 bit output binary code B(J) representing thermometer code T(J). Encoders E(1) through E(J-1) produce M-bit output binary codes G(1) through G(J-1), respectively, comprising the lower M bits of a binary code representing thermometer codes T(1) through T(J-1), respectively, where M is an integer greater than 1. Output encoder D processes codes G(1) through G(J-1) and B(J) to produce a set of digital output signals representing a binary code Y representing input thermometer code T.

Abstract: A crosspoint matrix with integrated matte generators includes double buffered internal storage registers which may be serially loaded with mode and selection data to enable the crosspoint matrix to operate in a crosspoint mode wherein a selected input bus is directed to selected output bus. Further, the crosspoint matrix may be operated in a matte generator mode wherein the stored data is supplied to the output bus as a matte signal. The matte signal may be selectively toggled through a series of values to enable operation with both D1 and D2 signals. The data is latched in response to a vertical pulse which enables data values to be written in non-real time as a background task while the actual switch of data is accomplished only upon receipt of a vertical pulse.

Abstract: A circuit for driving a transmission line composed of first and second conductors, comprises input transistors for providing a differential signal, and first and second output transistors having their bases connected to receive the differential signal, their collectors connected to a first reference potential level, and their emitters connected to the first and second conductors respectively. An output enable circuit selectively places the output transistors either in a conductive condition, in which they apply the differential signal to the transmission line, or in a non-conductive condition, in which the isolate the transmission line from the input transistors.

Abstract: A shaped video having an input key control signal associated therewith is processed by carrying out a first operation on the input key control signal to provide a first processed signal, carrying out a second operation on the first processed signal to provide a second processed signal, and combining the shaped video signal and the second processed signal to provide an output video signal. One of the first and second operations comprises translation. In this manner, a simulated shadow is added to the shaped video signal.

Abstract: A control panel for a television digital special effects device comprises a plastic shroud that has an internal conductive coating and defines a key panel cavity. A key panel plate fits within the key panel cavity. A thin stainless steel EMI screen is adhesively bonded to the upper surface of the key panel plate and an overlay sheet is adhesively bonded to the upper surface of the EMI screen. Apertures for the keys, controls and displays of the control panel are present in registration in the key panel plate, the EMI screen and the plastic overlay. The EMI screen has a main body with fingers projecting from its periphery. The dimensions of the main body of the EMI screen are smaller than the corresponding dimensions of the key panel cavity in the plastic shroud, while the finger-tip-to-finger-tip dimensions of the screen are larger than those corresponding dimensions.

Abstract: An enhanced video special effects system architecture is based on deinterlacing (16) incoming fields of interlaced video and processing the deinterlaced video through video special effects operations (18, 30), each of which benefits from operating on a progressive scan video signal rather than an interlaced video signal.

Abstract: An inverse hyperbolic comb filter decodes an encoded signal by subtracting a vertically filtered and horizontally filtered version of the encoded signal from a delayed version of the encoded signal whereupon the resulting output is further horizontally filtered to provide a first decoded output. A twice delayed version of the input signal then has the first output signal subtracted therefrom to provide a second output. Optional further vertical filtering may be employed to vertically filter the output of the first subtractor before the final horizontal filtering is performed. The filter may also be employed in encoding signals wherein the components to be encoded are first filtered prior to combining. The inverse hyperbolic comb filter is applicable to any system employing combining of two-dimensional signals via quadrature modulation and may also be employed in three-dimensional systems.

Abstract: A reduced viewport feature for a graphics display system allows an operator to observe manipulations on a graphics display of video image planes that are wholly or partially outside a viewing area. A two-dimensional input image plane in the form of a wireframe is transformed to a three-dimensional image plane due to manipulation, such as rotation and/or translation. The resulting three-dimensional image plane is subsequently mapped as a two-dimensional projection onto the graphics display. Transformation matrix coefficients are multiplied by a variable reduction coefficient to cause all points of the image plane to converge toward the center of the graphics display, resulting in the ability to view space which originally was not visible to the operator on an output video monitor.

Abstract: A digital architecture for a pulse generator includes a triggerable voltage controlled oscillator (VCO) with two alternative sources of frequency control voltage, an internal DAC or a phase frequency comparison with an external timebase. In a top octave of operation, the output of the triggerable VCO is used to produce output pulses whose edge locations are then adjusted by small digital increments or "slivers" and very small analog increments or "verniers". In lower octaves of operation, the contents of a pattern RAM serve to frequency divide the triggerable VCO output frequency by powers of two. The RAM contents are converted to a serial bit stream that imposes the coarse pulse width and period as an integral number of top octave periods, or quanta. The edge locations are then adjusted with slivers and verniers, as in the top octave. Automatic calibration facilities are included.

Abstract: A chroma key generation method and apparatus are provided (for both composite and component video) in which an operator selects a reference portion of a color television image to identify it as the background of the image, and a strobe signal is then generated whenever the video data that is presently passing through the keyer is within the reference portion of the color video image. This strobe causes the video data corresponding to that portion of the image to be stored. A microprocessor then determines attributes of the video in the reference portion of the color image from the stored video data, these attributes including a reference hue, .alpha.. The image hue .THETA. at each pixel in the color image is correlated with the reference hue .alpha. to produce a correlation signal that has a first range of values for points of the color image at which the image hue matches the reference hue and a second range of values for points of the color image at which the image hue does not match the reference hue.

Abstract: A mechanical holder for receiving an integrated circuit chip and an etched circuit board probe and holding them in predetermined relative positions includes an alignment block including alignment elements and having a main surface against which the probe is positioned, and a chip receiver having a main surface and including alignment elements that are complementary to the alignment elements of the alignment member. The chip receiver is attached to the alignment member with the main surface of the chip receiver in confronting relationship with the main surface of the alignment member and with the alignment elements of the chip receiver in registration with the alignment elements of the alignment member. The chip receiver defines a cavity that opens at its main surface.

Abstract: A video signal in component form is processed by generating high frequency linear color component signals from wideband linear color component input signals. The high frequency linear color component signals are combined to produce a high frequency linear luminance component signal, which is combined with color component signals that contain low frequency components present in the wideband linear color component input signals to produce high-frequency-corrected linear color component signals.

Abstract: A pseudo-random pattern generator has modifiable feedback so that a variety of pseudo-random video patterns can be generated and used either directly, or after further manipulation, to control the mixing of two video sources. Control of a multiplexer allows a variety of pattern lengths to be selected by altering which stages of a shift register are supplied to a feedback exclusive-OR gate. Patterns with controllable granularity can be achieved by stretching each part of the noise pattern a selectable number of times along either or both axes. Horizontal stretching is achieved by clocking the shift register more slowly than the rate at which it is being read out. Vertical stretching is achieved by repeating the same pattern on each of a selectable number of consecutive lines. Varying the ratio of the stretching along the horizontal axis to the stretching along the vertical axis allows the aspect ratio of the grains of the pattern to be controlled.

Abstract: An interpolating digital signal clipping circuit provides pre-clipping of the luminance component of a video signal. A difference circuit adjusts each sample so that a single bit indicates whether the sample value is closer to a positive or negative clipping limit. Interpolated samples are produced by phase shifting FIR filters and are applied, along with the actual current sample, to a minimum or maximum selecting circuit that selects the minimum or maximum sample depending on the state of the indicating bit. The selected sample is compared with the clipping limits to produce an excess signal that indicates how much the selected sample exceeds the relevant clipping limit. A gain control signal is generated to be a "1" when no clipping is required and less than one when clipping is required. A digital video signal clipping circuit receives this pre-clipped luminance signal and adjusts each sample as above.

Abstract: An apparatus and method for producing improved adaptive control signals for a luminance and chrominance separation circuit employing adaptive filtering of a chrominance signal includes a vertical difference detector, a horizontal difference detector, and a combiner. The vertical difference detector contains upper difference detector and lower difference detector, each of which receives a horizontally filtered next line signal (L.sub.N), a horizontally filtered present line signal (L.sub.P), and a horizontally filtered last line signal (L.sub.L), and which produce, respectively, an upper difference signal and a lower difference signal. In a preferred embodiment, the lower and upper difference detectors implement, respectively, the expressions .vertline.2L.sub.L +L.sub.P -L.sub.N .vertline. and .vertline.2L.sub.N +L.sub.P -L.sub.L .vertline..

Abstract: A probe for testing integrated circuits includes a stiff elastic substrate including a conductive plane, the substrate having a major portion with fingers projecting therefrom in cantilever fashion. A layer of dielectric material is adhered to the substrate and has a main surface remote from the substrate. A plurality of conductor runs are adhered to the layer of dielectric material at the main surface thereof. The conductor runs extend over at least some of the fingers and are configured to form transmission lines when the conductive plane is connected to a reference potential level.

Abstract: A digital architecture for a pulse generator includes a triggerable voltage controlled oscillator (VCO) with two alternative sources of frequency control voltage, an internal DAC or a phase frequency comparison with an external timebase. In a top octave of operation, the output of the triggerable VCO is used to produce output pulses whose edge locations are then adjusted by small digital increments or "slivers" and very small analog increments or "verniers". In lower octaves of operation, the contents of a pattern RAM serve to frequency divide the triggerable VCO output frequency by powers of two. The RAM contents are converted to a serial bit stream that imposes the coarse pulse width and period as an integral number of top octave periods, or quanta. The edge locations are then adjusted with slivers and verniers, as in the top octave. Automatic calibration facilities are included.

Abstract: An electronic instrument is provided with a shielding system consisting of two metallic shields press fitted into plastic instrument case parts without the need for any additional parts to provide electrical and mechanical attachment. In one embodiment, a bottom shield is press fitted onto protuberances inside of a lower case part and electrically connected to a common jack base on a circuit board within the instrument by a vee spring on the bottom shield. A top shield is press fitted into a capturing region of a switch support case part and includes an extension arm and extension ring that is mechanically held by case screws and guides already required by the plastic case. In that position, the extension ring is held in electrical contact with a common pad on the circuit board, the common pad being in electrical contact with a common trace, a common area, and the common jack base.

Abstract: An apparatus for providing an electrical connection between an electrical connector and a conductive chassis member includes aligned connector holes in the chassis, a thin ground sheet of springy and conductive material and a thicker support plate. The holes in the thin ground sheet have a periphery that includes alternating gaps and extensions, with the dimension defined by the gaps being larger than the corresponding dimension of the barrel of the electrical connector and the dimension defined by the extensions being smaller than the dimension of the barrel. The thin ground sheet is held in physical and electrical contact with and parallel to the conductive chassis member by the support plate, which is also preferably of conducting material, and a set of screws.

Abstract: A multiple video preview system for a production video switcher or digital effects device compresses a plurality of input video signals taken from various points along a video path through the switcher or effects device. The compressed input video signals are stored in a display memory in respective designated regions. The display memory is read out in a raster scan manner. The readout of a portion of the display memory occurs simultaneously with the storing of the compressed input video signals occurs in another portion of the display memory to provide a realtime video output signal that includes each input video signal in a compressed form. The video output signal is input to a monitor to display the input video signals simultaneously.