Abstract: An acceleration and scan expansion lens system for use in an electron discharge tube provides scan expanion in which the amount of scan expansion provided in the horizontal direction is independent of the amount of scan expansion provided in the vertical direction. In a preferred embodiment, the lens system (10) is employed in a cathode-ray tube (12) which has greater deflection sensitivity in the vertical direction than in the horizontal direction. The lens system includes a mesh electrode structure (62) that has a dome-shaped mesh element (66) which is supported by an electrically connected to a metallic cylindrical support element (70). The dome-shaped mesh element is formed to have a concave surface as viewed in the propagation direction (35) of the electron beam and is of rotationally symmetric shape. The lens system also includes an annular electrode element (64) that has an aperture of elliptical shape and is positioned adjacent the output end of the mesh electrode structure.

Abstract: A voltage regulator for an anode voltage supply in a CRT powered by a deflection flyback pulse generator includes a voltage sensing network for providing a feedback signal to a summing amplifier. A pulse sensing network which may be a capacitive divider is connected between the output of the flyback pulse generator and the input to the summing amplifier. The resultant output of the summing amplifier is the flyback pulse level shifted with respect to a DC level which is applied to a MOSFET switch to turn it on whenever the flyback pulse goes above the MOSFET's threshold. The output of the MOSFET switches current through a shunt capacitor coupled to the output of the deflection flyback pulse generator for altering its capacitance thereby regulating the height of the flyback pulses, and thus regulating the anode voltage supply.

Abstract: A current signal limiter provides precise minimum and maximum current limiting. Both maximum and minimum current limits are easily programmable. The signal limiter operates at maximum frequency response without inversion of the input signal. Current signal limiting is achieved by an NPN transistor biased in a common base configuration with the base coupled to a reference voltage source and the collector providing the output current, a series diode coupled to the emitter of the transistor for receiving a trickle current which prevents the transistor from turning off as well as setting a minimum current limit, and a diode matrix for receiving two reference currents and an input current. The diode matrix steers the input and reference currents to the transistor or to the reference voltage source, depending on the magnitude of the input and reference currents. The minimum and maximum current limits are programmable by adjusting the values of the reference currents and the trickle current.

Abstract: A clock-delay circuit for a sinusoidal clock output includes a pair of current amplifiers, each connected to the clock output, wherein one of the amplifiers generates an amplified signal in phase with the clock output and the other generates a signal shifted in phase by 90.degree.. Both signals are multiplied by control signals to alter their respective amplitudes prior to summation of both multiplier outputs. The sum of the multiplier outputs will be a sinusoidal waveform whose phase depends upon the control currents in the multipliers which are set by the user. Thus, the circuit provides a user-controlled continuously variable delay for a sinusoidal clock.

Abstract: A high density connector in which the conductive leads of at least two circuit boards, two flexible circuits, or one of each are interconnected directly without the use of a traditional molded connector with pins captured therein. This is accomplished by overlapping the two boards with the conductive paths on each to be interconnected facing each other. An anisotropic elastomeric polymer material is inserted between the boards and then the sandwich is clamped together compressing the polymer material to provide a low electrical resistance path therethrough to interconnect the conductive paths on the respective circuit boards. One disclosed embodiment utilizes backing plates above and below the sandwich with a plurality of screws passing through registration holes to align the conductive paths and to provide closure of the connector. The other disclosed embodiment is designed to interconnect two boards along substantially the full width of the boards.

Abstract: A multistage digital filter for producing an output data sequence in response to elements of an input data sequence includes a multiplier for multiplying elements of the input data sequence by selected coefficients to produce product terms. An accumulator sums product terms to produce elements of a first filter stage output sequence and elements of the first filter stage output sequence are sequentially fed back to the multiplier. The multiplier and accumulator produce accumulated sums in response to the first stage output sequence to provide a second filter stage output sequence. In a similar fashion, each filter stage output sequence is fed back to the multiplier as the input sequence to the next filter stage until the output sequence of the last filter stage is produced.

Abstract: The present invention constitutes a cursor image (36) for use in graphics imaging systems for providing images with three-dimensional qualities. The cursor indicates position within a three-dimensional space. The cursor comprises a reference symbol (38) located at a reference point (58) on a reference plane (60), a pointer symbol (40) located pointing to the position (42), and a tether symbol (44) connecting the reference symbol and the pointer symbol. The cursor image includes depth cue features which assist the observer in gauging the depth of the position being indicated. The cursor is preferably displayed with a stereoscopic imaging system (10) employing a liquid crystal stereo switch unit (16). In such a system the cursor image is displayed on a cathode-ray tube (12) in left and right perspective projections (46) and (48) of differing binocular disparity which are used by the observer to form a single three-dimensioinal image of the cursor.

Abstract: A digital oscilloscope processes digitized input waveform data sequences according to a user defined mathematical expression to compute a processed waveform data sequence controlling a periodically updated waveform display on a screen. The waveform data is computed during equivalent time computation passes during each of which pass every Nth data of the waveform data sequence is computed. The first waveform data computed during each pass is selected in a pseudorandom fashion such that each data of the waveform data sequence is computed once every N computation passes. The value of N is suitably chosen so that the duration of each pass is substantially equal to the period between waveform display updates.

Abstract: An f.sub.T quadrupler amplifier improves the frequency response beyond that which is possible with an f.sub.T doubler, yet retains precise nonlinearity correction.Voltage to current conversion is achieved by two parallel differential transconductance signal amplifiers. Two of the inputs of the signal amplifiers are coupled together to form one main differential input, whereas the other two inputs are coupled together and to ground or to a reference voltage. The outputs of the signal amplifiers are cross coupled to form a main differential current output. A parallel differential transconductance error amplifier is provided which senses an error voltage generated by the main signal amplifiers. A corresponding error correction current is generated by the parallel error amplifier and returned to the parallel signal amplifiers. This error correction current substantially reduces nonlinearities in the output current of the signal amplifiers.

Abstract: X-ray attenuating ceramic materials having at least one substance selected from the group including compounds of strontium, zirconium, yttrium, niobium, molybdenum, neodymium and tungsten are disclosed. A zinc compound can be used for fluxing and X-ray attenuation in certain ceramic materials. The materials can be formed into strong, non-porous bodies such as cathode ray tube funnels. Such materials include forsteritic porcelains manufactured from batches containing strontium zirconate. Other X-ray attenuating ceramics contain a mixture of X-ray attenuating substances, including a compound of barium.

Abstract: A charge-coupled device comprises a substrate of semiconductor material having at least two buried channels formed therein. At least two sets of clock electrodes overlie the buried channels. By application of appropriate potentials to the clock electrodes, an electrical charge may be propagated in controlled fashion along each buried channel towards its output end. A floating diffusion is formed at the output end of each buried channel for receiving charge propagated along the channel. Output transistors are assoicated with the buried channels respectively and each has a control electrode connected to the floating diffusion of the associated channel. An output diffusion is located between the floating diffusions and the control electrodes of the transistors and extends perpendicular to the channels.

Abstract: A digital bandpass oscilloscope permits an operator to observe both time and frequency domain plots of analog signal components of frequency within a passband of selected center frequency during a time window of selected duration. The input signal is digitized, and the resulting digital data sequence is bandpass filtered and decimated by an adjustable decimation ratio to produce stored waveform data indicating the time dependent behavior of the passband during the time window. The oscilloscope, which utilizes the waveform data to produce both time and frequency domain displays of the passband, adjusts the decimation ratio to ensure that the number of data elements in the waveform data sequence is constant regardless of the selected duration of the time window and adjusts the bandwidth of the passband to minimize aliasing in the time domain display.

Abstract: An apparatus for generating a trigger signal in response to a selected pattern of events includes event synchronizers for generating synchronized event signals of states indicating the current state of each event on the falling edge of each pulse of a clock signal. A programmable encoder provides a set of event encoding signals of states set according to selected patterns of synchronized event signal states. A set of bus drivers actively drives the potential of each conductor of a bus high on the falling edge of each clock signal pulse and actively drives the potential of selected conductors of the bus low on the rising edge of each clock signal pulse, the conductors being selected according to the pattern of event indicating signal states generated by the encoder.

Abstract: An adjustable delay element for digital systems includes a high-pass filter in parallel with a low-pass filter. The high-pass filter passes the higher frequency component of the digital signal and the low-pass filter passes the lower frequency component to introduce a delay into the digital signal. A current multiplier directs a selectable portion of the higher frequency component to aid or oppose the lower frequency component to vary the delay within the signal. An output stage receives the lower frequency component with the selected portion of the higher frequency component and reproduces the digital signal with the delay. Embodiments for both differential and single-ended versions of the corresponding delay element are disclosed.

Abstract: A pin driver circuit for driving a digital integrated circuit is capable of producing symmetrical rise and fall characteristics, yet is suitable for implementation in monolithic bipolar integrated circuits. This circuit includes a pair of matched transconductance amplifiers, one at each end of an output resistor, connected between a voltage source and a return voltage. Each amplifier has one of a pair of equal resistors between its input terminal and high output terminal to develop an equal swing voltage on alternate ends of the output resistor when a swing voltage current source is switched between the two input resistors by a control signal. The output is taken from the junction between the output resistor and the low output terminal of the amplifier at the high end of the output resistor.

Abstract: A timing pulse jitter measurement display suitable for observing large jitter deviations, such as those caused by head changes between fields of video data in a video tape or cassette recorder (VTR or VCR), selects a range of data samples about each timing pulse for processing. The data samples are acquired using a stable, jitter free, precision clock. Residual signals, such as residual subcarrier in a video signal, are removed from the selected data samples and a precise timing point is determined for each timing interval with respect to a stable reference point. The deviations of the timing points from a baseline, derived from the precision clock and representing the stable reference points occurring at a nominal timing interval, are displayed, and means provided for determining peak to peak jitter along any portion of the acquired set of displayed data samples. Averaging also is provided between acquisition sets of data samples to reduce noise and highlight phase errors due to some repetitive influence.

Abstract: A two-dimensional array of binary values is used to control operation of a bi-level imaging device. The array of binary values is formed by applying an enhanced array g(u,v) to a two-dimensional array of threshold values. A two-dimensional array of pixel value f(u,v) is used to form the enhanced array g(u,v) such that g(u,v)=m.sub.f +k[f(u,v)-m.sub.f ] where m.sub.f is the average value of f(u+a, v+b) from a=-L to a=+L and b=-M to b=+M and k is a gain function which depends on the standard deviation in f(u+c, v+d) from c=-N to c=+N and d=-P to d=+P. L, M, N and P define the sub-array over which the standard deviation is calculated. Preferably, L, M, N and P are each equal to 2. The value of k is a decreasing function of the standard deviation: the larger the standard deviation, the smaller the gain factor k. The rate at which k decreases with increase in the standard deviation depends on the edge sampling characteristics of the array of threshold values.

Abstract: A level detecting waveform digitizer for repetitively sampling an analog waveform and converting analog samples into representative digital data is provided with a predictive time base circuit for accurately controlling sample timing with respect to a triggering event in the input waveform and a comparator for indicating when the magnitude of the waveform as indicated by the digital data exceeds a predetermined level. The digitizer also includes a counter for counting samples taken and a second comparator for indicating when the sample count reaches a predetermined limit.

Abstract: A time variant frequency correction technique uses a frequency conversion circuit to obtain an intermediate frequency and an adjusted local oscillator frequency from an input signal frequency, a local oscillator frequency and a reference oscillator frequency. The intermediate frequency and adjusted local oscillator frequency are simultaneously counted during a period determined by the reference frequency. The resulting counts are used to calculate the input frequency independent of time variations in the local oscillator frequency for display on a display device.

Abstract: A delay circuit generates an output signal that changes state in adjustably delayed response to a state change in an input signal, the delay being adjusted by a control signal. A series of buffers produces a plurality of delayed signals that change state at different times in response to state changes in the input signal. Amplifiers amplify the input and each delayed signal to produce output currents that are summed to provide a load current through load resistors, thereby providing the output voltage across the load resistors. The gain of each amplifier is adjusted in accordance with the control signal such that at least one and not more than two of the amplifiers have non-zero gain. The delay provided by the delay circuit is determined by the relative gains of the amplifiers.