Abstract: A first pair of input data words represent two adjacent pixels on a first line of a first field of a video signal in interlaced format, a second pair of input data words represent two adjacent pixels of a first line of a second field of the video signal, and a third pair of input data words represent two adjacent pixels of a second line of the second field. The first and second lines of the second field are adjacent lines in that field and the first line of the first field is between the first and second lines of the second field. The positions on their respective lines of the pixels represented by the second and third pairs of input data words correspond to the positions on the first line of the first field of the pixels represented by the first pair of input data words. The first, second and third pairs of data words are read from memory, and are processed by interpolating among them to generate an output data word.

Abstract: A method and apparatus is disclosed which provides for the placement of a border video signal around a selected object in a video image. A video image of the selected object is first inserted into a video image of a selected border video signal in a video mixing process by use of a key signal defining the selected object. The key signal is further processed to transform the step transitions associated therewith between the zero and full insert states into non-step transitions. The transformed key signal is thereafter used to control a subsequent mixing of the resulting image of the selected object inserted into the video image of the border video signal with a background image to produce a composite video image.

Abstract: An output video signal is derived from an input video signal by writing the input video signal into a frame buffer, generating a sequence of address words, modifying the sequence of address words, and using the modified sequence of address words to read the video signal from the frame buffer. The sequence of address words is modified by comparing each address word of the sequence with a reference word that defines a predetermined location of the scene represented by the input video signal, and combining each address word that defines a location of the input scene having a selected spatial relationship with the predetermined location with an offset word.

Abstract: An input video signal representative of a scene is processed by carrying out a spatial transform operation on the input video signal so as to generate a transformed video signal. Concurrently, an input key signal representing the opacity of the scene and comprising a stream of digital data words is written into a key frame buffer. A first sequence of address words is generated, and a transform operation is carried out on the first sequence of address words so as to generate a second sequence of address words. The second sequence of address words is used to read digital data words from the key frame buffer so as to generate a first transformed key signal. The transform that was carried out on the first sequence of address words is such that the first transformed key signal is spatially transformed with respect to the input key signal in the same manner as the transformed video signal is spatially transformed with respect to the input video signal.

Abstract: A switch for selectively routing a signal to a receiving device for interrupting the transmission of said signal to said receiving device includes two latches, a differential delay circuit, and a buffer amplifier. State commands to individual switches in a routing system can be preset asynchronously by one latch and all of the switches in the system can be enabled to change states simultaneously by triggering a second latch. The switch is also of the make before break type, i.e., it turns on more rapidly than it turns off. The switch also includes programmable current sources in the buffer amplifier stage. These current sources are programmable to provide full power when the switch is conducting and to provide only standby power when the switch is nonconductive.

Abstract: A device for providing a visual indication of the value of a variable of an electrical signal has a plurality, n, of driver circuits each having an input terminal for receiving the electrical signal and a plurality, m, of output terminals. Each driver circuit is operable in a mode in which it provides an output signal at its ith output terminal when the value of the variable lies in a range corresponding to the ith increment on a scale of m increments. The position of the scale of m increments associated with each circuit is adjustable so that the scale of m increment associated with the jth driver circuit overlaps by ((m-1)+(n-1)/n) increments the scale of m increments associated with at least one of the (j-1)th circuit and the (j+1)th circuit. Light emitting elements, arranged in an interdigitated grand linear array, are coupled to respective output terminals of the driver circuits.

Abstract: A video signal that is representative of a wide scene comprises signal elements corresponding to a plurality of horizontal line intervals of a raster. A luminance component and two chrominance components are included in each horizontal line interval, in time-compressed sequential relationship. The video signal also incorporates information representative of a number in the range from zero to the difference between the aspect ratio of the wide scene and the aspect ratio of a scene represented by a conventional video signal format. This information determines the portion of the wide scene that is represented by a video signal of the conventional format derived from the video signal representative of the wide scene.

Abstract: An actuator mechanism, particularly for a potentiometer, comprises a mounting frame defining an interior space. An elongate rotary shaft traverses that space. A lever arm is secured to the shaft and extends radially away from the longitudinal axis of the shaft within the space defined by the mounting frame. The mounting frame has two substantially parallel surfaces that confront the lever arm, and respective friction assemblies are interposed between the lever arm and those two surfaces respectively. Each friction assembly comprises a body of friction material engaging one of the two parallel surfaces, and a compression spring that urges the body of friction material against that surface. The body of friction material and the spring are maintained captive between the lever arm and the surface of the frame that is engaged by the body of friction material.

Abstract: A buck regulator circuit including an inductance is provided with an input current via a pass transistor and a second transistor disposed in drive relation to the pass transistor. The second transistor supplies current to the inductance at a tapped connection so the second transistor may drive the first transistor at a voltage level sufficiently high for saturating the first transistor.

Abstract: A circuit for converting ECL logical signals into TTL logical signals comprises a differential amplifier defining two current paths leading to a negative reference potential source. When the ECL input signal is logical zero, the first current path is closed and the second current path is open, and vice versa when the input signal is logical one. A first transistor has its base connected to the first current path and its emitter connected to a positive reference potential source, and is biased by a load resistor connected to the first current path. A second transistor has its emitter connected to the collector of the first transistor and its base connected to the second current path, and is biased by a second resistor. When the input ECL signal is logical one, the first current path is open and the first and second transistors are on and off respectively, the potential at the output terminal of the circuit being limited by a clamping diode connected between the base and collector of the first transistor.

Abstract: A differential input receiver having normal and common mode impedance balanced inputs and a common mode rejection ratio approaching infinity is provided. The receiver includes a differential input operational amplifier across which is connected a fixed gain inverting amplifier. The fixed gain, inverting amplifier being connected in a feedback configuration across the differential input amplifier. Additionally, the values and ratios of the various resistors being selected to provide the balanced differential input and the substantially zero common mode gain of the receiver.

Abstract: A circuit receives an input logical signal of one polarity and converts it into two balanced logical output signals of the opposite polarity. The circuit comprises two resistors connected between a reference potential source of the polarity of the output signals and the terminals at which the output signals are provided. The circuit also comprises a current source. Each resistor has a resistance value such that when it is traversed by the current from the current source the potential difference between its ends is equal to the difference between the two possible potential levels of the output signals. A differential switching device responds to the input signal being at a first potential level by connecting one of the output terminals to the current source and isolating the other output terminal from the current source, and vice versa when the input signal is at a second potential level.

Abstract: The 50% point of the leading edge of sync is used to acquire the value of a color burst locked CW carrier, and a quadrature color burst locked CW carrier. The acquired value of each of the two carriers are split into two values representing the value on alternating horizontal lines. This requires the generation of a one-half horizontal rate signal (H/2) which can have an arbitrary phase relationship. The H/2 phase is associated with each of the four acquired CW carrier values and that information is used by the computing device. The H/2 signal is also used to gate a 30 Hz vertical frame pulse to enerate a 15 Hz V1 color frame pulse. The computing device receives the color frame pulse and records the time the pulse occurs. This information represents the minimum and sufficient set of data to obtain a complete measure of sync to subcarrier phase (SC/H) and color frame comparison.

Abstract: A chroma keying system which prevents the production of a chroma key signal when the primary color signals are equal is described. This system effectively prevents chroma keys on monochrome portions of color foreground camera signals. These monochrome portions are typically caused by uneven studio lighting and the resulting shadows and reflections. The system includes a comparator which compares the R, G, and B signals and generates an inhibit signal therefrom. This inhibit signal is then used to prohibit the generation of a chroma key signal.

Abstract: An electronic circuit which produces controlled rise and fall times with a sine-squared step pulse shape from rectangular input pulses is disclosed. The circuit uses the inherent nonlinear behavior of a bipolar transistor differential pair to shape the pulses and requires very little passive filtering. The output wave-shaped current may be developed across a resistor or fed to the input mode of a feedback amplifier.

Abstract: A circuit for reducing the effects of negative-going impulse noise in composite television video signals has on sync separators is disclosed. A variable output current source is used to supply rundown current to a dc restorer in a sync separator. A retriggerable monostable multivibrator is triggered by negative-going impulse spikes in the composite video signal. The output of this multivibrator is coupled to the current source to increase its output and therefore decrease the time required for the dc restorer to recover from the negative spike.

Abstract: A special effects generator for use in video switching whereby a three dimensional shadow effect is produced by utilizing luminance information separately derived from RGB color inputs and providing a separate multiplier to control the shadow density. The generator functions by controllably blanking a portion of one video signal and then replacing such portion by another video signal and switching the displayed video linearly, said switching being controlled by color differences in one of the video signals, and providing luminance information derived from one video signal as a control signal for application to the other video signal so as to reduce the level thereof.