Abstract: An optical scanning system for a compact disc having a sinusoidal data track radially meandering, at a selected frequency, about the axis of rotation of the disc includes a first laser beam for reading data from the data track. A +1 level laser beam and a -1 level laser beam respectively track the opposite edges of the data track and generate a tracking error signal. The +1 level laser beam and the -1 level laser beam are separated, with respect to the disc, by a distance equal to an odd integer multiple of one half the wavelength corresponding to the selected frequency. The +1 and -1 laser beams are not modulated by the sinusoidal data track and standard tracking circuitry can be used to track the data track.

Abstract: A system for regulating the transfer impedance of a plurality of current-to-voltage converters to a substantially equal value includes a reference voltage source and a reference impedance for providing a reference current. A reference current-to-voltage converter is responsive to the reference current and provides an output voltage. A comparator is responsive to the reference voltage and the output voltage and provides a control signal to the reference current-to-voltage converter and to all the other current-to-voltage converters to maintain the transfer impedance of all the current-to-voltage converters constant.

Abstract: An improved cathode ray tube has a shrink-fit implosion protection band surrounding a portion of the tube envelope. The band includes a plurality of lugs for supporting the tube. The improvement comprises the band including a plurality of embossments arranged around the band. The embossments extend outwardly from the tube for a preselected distance to form cavities between the tube envelope and the embossments. The embossments include smooth outer surfaces to which the lugs are attached by welds. The embossments have indentations at the locations of the welds that extend into the cavities. The cavities have depths greater than the depths of penetration of the indentations into the cavities. By utilizing the embossments, the indentations, caused by welding, remain out of contact with the tube envelope.

Abstract: A holding device for holding a record (CD) in a magneto-optical recording/playback device includes a first wheel (R1) pressing against one side of the record. A first pivotable arm (AR1) supports a second wheel (R2), motion of the first arm moves the second wheel against the other side of the record and also centers the record in the holding device. A second pivotable arm (AR2) supports a magnet (M). A lever includes a third pivotable arm (AR3) mounted on an axis (A3) supported by the first pivotable arm and is in contact with the second arm. A fourth pivotable (AR4) arm pivots in a direction opposite from that of the third pivotable arm. A stop (AS) is in the proximity of the fourth pivotable arm. Accordingly, motion of the first arm (AR1) away from the record causes the third arm (AR3) to force the second arm (AR2) away from the record and also causes the fourth arm (AR4) to hit the stop (AS) and cause the third arm to move the second arm further and the magnetic head (M) away from the record.

Abstract: A mount for mounting a lens in an optical scanning device includes a tubular portion having a first surface which rotatably supports the lens. A second surface includes a plurality of arcuate supports. An annular spring is supported by the arcuate supports and is bent at the points of contact with the supports to extend outwardly beyond the supports to bias the mount and the lens against the scanning device in which it is mounted.

Abstract: A bit-serial integrator includes the cascade combination of a bit-serial adder, a first bit-serial register and a second bit-serial register. Input signal is applied to one input of the adder and the output terminal of the second bit-serial register is coupled to a second input of the adder. A transparent latch is coupled to an output of the first bit-serial register and is conditioned to pass a predetermined number of sample bits and then to latch and output a particular sample bit for the duration of a sample period. The output of the latch is an integrated, scaled and truncated representation of the input signal.

Abstract: A processor which expands a compressed video signal is disclosed. The compressed video signal applied to the processor is generated by partitioning a video image into segments and then describing how each segment is filled by using a bilinear equation, that is to say, a linear equation which is a function of a horizontal coordinate X and a vertical coordinate Y. The coefficients of the X and Y coordinates each include integer and fractional parts. The circuitry develops a table of values from the coefficient of the X coordinate by repeatedly adding the coefficient in an accumulator. As each sum is produced, the integer part of the sum is stored. The table of values is developed from the stored integer sums as the difference between alternate sums, where successive alternate pairs of sums are interleaved. For example, the table would include the difference between the first and third sums followed by the difference between the second and fourth sums, then the third and fifth sums and so on.

Abstract: Computer generated video objects may be superimposed over a background video image so as to create the illusion of a single composite scene. The leading edge of an object is detected and for a period of time the object and background video signals are mixed. After that period, only the object video is tranmsitted. Upon detection of the object's trailing edge, the two video signals are again mixed for a period of time. After this latter period, only the background video signal is transmitted until another object's edge is detected.

Abstract: Apparatus for approximating a signal k(b) useful in controlling a Broadcast Television Systems Committee (BTSC) expander circuit where k(b)=R(b+1)/(b+51) and b is the root-mean-square (RMS) value of an applied signal. In order to generate the control signal k(b), the signal, b, is scaled by a first coefficient. The signal, b, is squared and scaled by a second coefficient. The scaled signal and the squared and scaled signal are combined with a constant value to produce a signal approximating the signal k(b).

Abstract: A parallel-pipeline video signal processing system is disclosed which includes a statistical decoder, an arithmetic and logic unit and a pixel interpolator which operate in parallel under the control of sequencing circuitry to expand a compressed video signal. The video signal may have been developed using a variety of compression techniques including Huffman-type statistical encoding.

Abstract: A secondary video signal is sampled, digitized and combined with an in-memory switching signal. The combined digital signal is stored in a random access video memory. The stored signal is read out in synchronism with the synchronizing signal components of a primary video signal. The switching signal is recovered from the output of the memory, and compared with a content code signal to develop a fast switching signal. A video output switch, coupled to receive the primary video signal and the stored secondary video signal and responsive to the fast switching signal, applies an appropriate one of the two input signals to the kinescope to define a secondary inset picture within a large primary picture.

Abstract: An antialias filtering and subsampling system incorporates a compound accumulator including three cascade connected accumulator circuits conditioned to integrate and dump the integrated values of n input samples. The integrated values from the three integrators are scaled, delayed and combined to produce substampled values of a signal which has been filtered according to the transfer function [sin(n.pi.ft)/nsin(.pi.ft)].sup.3.

Abstract: A circuit for separating FM signals from a composite signal utilizes a comb filter having successive frequency response nulls which span the frequency spectrum of the FM signal to be separated. The comb filter response is phase linear and defines the pass-band of the desired signal. A nonideal or phase nonlinear bandpass filter can be cascaded with the comb filter to attenuate out of band signals. The cascade combination of the comb filter and nonlinear bandpass filters is a cost effective substitute for the conventional, complicated phase linear bandpass filter having a boxcar frequency response traditionally used to separate FM signals.

Abstract: Computer main memory is used for storing relatively densely sampled green and detail information concerning a television display and for storing relatively sparsely sampled red information and blue information concerning the same television display. The relatively densely sampled green and detail information is read out in substantially real-time from computer main memory during line trace intervals in the television display. The relatively sparsely sampled red information and blue information are read out of computer main memory in advanced and compressed time during selected line retrace intervals in the television display.

Abstract: In an NTSC digital television receiver, the composite video signal is digitized with a sampling frequency of 32/13 times the color subcarrier frequency, f.sub.c. The chrominance signal component of this video signal is demodulated using a pair of finite impulse responsive filters having programmable weighting factors. The weighting factors are changed in a 32 step sequence as 32 consecutive chrominance samples are applied to the filters. The circuitry which generates the weighting factors is responsive to a phase alignment signal to determine when the 32 step sequence begins.

Abstract: Computer main memory is used for storing relatively densely sampled luminance information concerning a television display and for storing relatively sparsely sampled chrominance information concerning the same television display. The relatively densely sampled luminance information is read out in substantially real-time from computer main memory during line trace intervals in the television display. The relatively sparsely sampled chrominance information is read out of computer main memory in advanced and compressed time during selected line retrace intervals in the television display.

Abstract: A digital arithmetic combiner having improved overflow signal propagation delay characteristics is disclosed. Such an arithmetic combiner includes a tristate device having a data input terminal coupled to an overflow input terminal and a data terminal coupled to an overflow output terminal. A tristate control terminal is coupled to the output of logic circuitry. The logic circuitry is responsive to operand input signals and enables the tristate device to generate a signal at its data output terminal when the operand input signals have different logic states. In addition, an overflow generator is responsive to the operand input signals, and generates a signal indicating overflow conditions at the overflow output terminal when the operand input signals have the same logic state.

Abstract: In field/frame recursive filters for providing noise reduction to composite video signal, inversion of the chrominance component of the composite video signal is obviated by selecting nearest neighbor in-phase field/frame delayed signals for recursion. The system arbitrates between two or more nearest neighbor in-phase signals or combinations thereof and feeds back the signal having an amplitude most closely matching the incoming composite video signal.

Abstract: Computer main memory is used for storing relatively densely sampled wideband video information concerning a television display and for storing relatively sparsely sampled narrowband video information concerning the same television display. The relatively densely sampled wideband video information is read out in substantially real time from computer main memory during line trace intervals in the television display. The relatively sparsely sampled narrowband video information is read out of computer main memory in advanced and compressed time during selected line retrace intervals in the television display. The wideband video information may be luminance information; and the narrowband video information chrominance information.

Abstract: A MOSFET analog signal squaring circuit is disclosed. A first MOSFET has a source electrode coupled to a bias voltage source, a gate electrode coupled to an input terminal, and a drain electrode coupled to an output terminal. A signal inverter is also coupled to the input terminal. A second MOSFET has a source electrode coupled to the bias voltage source, gate electrode coupled to the signal inverter, and a drain electrode coupled to the output terminal. A load impedance is coupled between the output terminal and a supply voltage source.