Abstract: A video signal processing circuit and method for the insertion of a blanking data signal including blanking pulse, horizontal sync and color burst signal components into an input video signal to provide a modified video signal. The modified video signal is subjected to signal shaping to reduce the slopes of the front and rear edges of the blanking pulse portion in order to suppress transient overshoot and ringing distortion when the resultant output video signal is transmitted through a low pass filter. The signal shaping is preferably provided by a voltage controlled amplifier whose gain control terminal is connected to a control voltage which varies during the blanking pulse and is provided at the output of a slew limited amplifier or a non-linear low pass filter with a sine squared pulse response. The input of the slew limited amplifier is connected to an electronic switch operated by a timing circuit for selectively switching between different gain voltage sources.

Abstract: A dual-flash analog-to-digital converter comprises a first quantizer (20) for quantizing an analog input in accordance with coarse amplitude levels and outputting a more significant bits signal (24) and a remainder analog signal (32); a second quantizer (34) for quantizing the remainder signal in accordance with fine amplitude levels to output a less significant bits signal (36); and digital corrective logic (38) which receives both digital signals and corrects carry errors in the quantization. An analog method of diagnosing errors in the operation of such circuit calls for applying the remainder signal (32) to a pair of comparators (45,46) having thresholds set at upper and lower ends of the normal quantization range of second quantizer (34).

Abstract: The present invention relates to a drive circuit for a stepping motor. The drive circuit provides a low voltage to the coils of the stepping motor in the steady state, and a high voltage to the coils when changing state. As a result, the state changes rapidly and the stepping motor is driven efficiently. The high voltage is derived from the energy which was stored in the winding of the stepping motor before the switching occurred by transferring that energy to a capacitor which achieves a charge potential that is greater than the potential of the power supply voltage.

Abstract: The method of cutting a plurality of boards or parts (20) from a number of stacked panels (10) which includes placing the panels upon a perforated fixture (2) including a plenum (14) such that the area beneath the perforated surface (4) may be evacuated. The stack of panels (10) are cut into boards or parts (20) the desired size and shape with the exception of a small tab (22) connecting each board or part (20) such that the entire panel (10) remains a unit. An impermeable sheet (24) such as plastic is placed over the top of the partially cut panels (10) and the space (14) beneath the partially cut panels is evacuated holding the parts in position. The tabs (22) are then cut and the boards or parts (20) removed.

Abstract: The instrument operating time recorder (10) is attached to host instrument (12) and includes a frequency divider (14) for counting line voltage transitions during power-on time and to generate a binary output for a prescaler (20). Prescaler (20) divides by a predetermined value set to the frequency of the host instrument and generates a signal for a digital decoder (24) the output of which can be applied to the readout or display (26).

Abstract: The present invention relates to a capability present within a graphics display terminal wherein a zoom operation may be accomplished, the width of each of the lines of the zoomed image being maintained at a one pixel width regardless of the degree or amount of magnification of the zoomed image. This is accomplished by utilizing the firmware stored in the processor to perform the magnification of the image therein, prior to the storage of the appropriate binary data in the video display memory, the binary data being the pixel representation of the displayed image. Since the magnification of the image takes place prior to storage of the binary data in the video display memory, the graphics display terminal of the present invention can use this binary data to display an image, a zoomed image, the width of each line being equal to, approximately, a one pixel width. Therefore, despite the degree of magnification of the zoomed image, a very discernable, clear image will be displayed on the CRT.

Abstract: A filter circuit for processing a composite video signal comprises a series circuit of a delay device for delaying an input composite video signal for the duration of one line of the video signal and a first bandpass filter connected to the delay device to receive the delayed video signal. A transversal bandpass filter receives the input composite video signal and provides as outputs a delayed composite video signal and a delayed chrominance component. A first summing device sums the delayed chrominance component and the output of the series circuit, while a second summing device sums the delayed composite video signal and the output of the first summing device. The series circuit can be selectively disabled so as not to apply the delayed video signal to the first summing device.

Abstract: A focus control circuit particularly well suited for use with a cathode-ray tube having a quadrapole lens includes automatic tracking focus and astigmatism features to ensure a well-focused display with minimum focus readjustment.

Abstract: A circuit is described for automatically controlling an input current to a current translating device having an output current functionally related to the input current. A sensing circuit detects the output current of the device and produces a control signal representative of the output current. The control signal is coupled to a control circuit that varies the input current to the device. In the preferred embodiment of the invention, the dynamic range of the sensing circuit is increased by coupling a constant current generator to its input.

Abstract: A scheme for digitizing a stationary video image is disclosed. The amplitude of a video signal, representing said video image, is sampled at a plurality of points along the time axis and is compared with the count in a counter. If the amplitude equals the count at a particular point on the time axis, the count is stored in a memory in a location corresponding to said particular point. The process is repeated until a count in the counter is stored in said memory in locations corresponding to all of said plurality of points along the time axis of said video signal. If two or more counters are used, each counting from a different initial value, and if two or more corresponding comparators are used to make the above comparison, the time required to digitize said stationary video image may be reduced. Consequently, the time required for the video image to remain stationary is reduced.

Abstract: A high-frequency differential amplifier is provided with a pair of buffer input stages, each having transistors the transconductance of which may be varied by varying a current source connected thereto. Since transistor frequency response and step response are dependent upon transconductance, bandwidth and damping factor of the step response may be varied for optimum performance without degrading gain and dynamic range characteristic of the differential amplifier. One useful application of the differential amplifier of the present invention is as an error amplifier in a cascomp amplifier circuit, such that the apparent damping factor of the step response of the cascomp circuit may be adjusted.

Abstract: A method and apparatus is disclosed for independently displaying one of a plurality of images on a display and for superimposing the plurality of images onto one another to produce a composite image. One or more bit planes are selected to constitute a group (defined to be a "surface"), and one or more additional bit planes are selected to constitute another group. The number of groups corresponds to the number of images to be independently displayed. The priority of one group over the other is selected. This ensures that the image from the one group (surface) appears to be "in front of" the images from the other group (surface) on the display. In the case of a color terminal, the colors associated with each group are selected. A color map memory contains a plurality of brightness indices which determines image brightness. Associated with each index is one or more color indices.

Abstract: A differential amplifier is provided with means to control the collector-to-emitter voltage thereof proportionately with quiescent current therethrough to dynamically maintain thermal balance therebetween when the gain setting is changed.

Abstract: The cascomp amplifier is modified to provide a dynamic biasing circuit which varies the bias point of the cascomp amplifier in proportion to the change in the true bias point of the main channel pair to allow full thermal V.sub.be error correction for overdrive conditions and for common-mode signals. A buffer amplifier senses the average voltage of the main channel input transistor emitters and generates a voltage proportional to this average which is added to the biasing network for the cascomp amplifier common-base amplifier transistors.

Abstract: A circuit test system using signature analysis allows random probing to detect faults in an assembly under test. Test points on a properly working assembly are probed at random and the signatures obtained are listed in a memory or storage media. Thereafter, when testing other boards these same test points are probed randomly and the signatures are compared to the list of possible good signatures. If a match is found a "pass" indication is generated and the operator tests another node. If a match is not found, a "failure" indication is generated and more detailed troubleshooting of circuits at that test node commences.

Abstract: A signal processing system employing charge transfer devices for fast-in slow-out operation is disclosed. A push-pull input analog signal is applied to two charge transfer devices, and the clock pulses applied thereto are shifted one-half clock cycle with respect to one another. The output signals from the two charge transfer devices are differentially summed, and thereby providing cancellation of dark current and clock related noise in the charge transfer device, and doubled sample rate.

Abstract: An improved signal input circuit suitable for use in wideband oscilloscopes includes a high impedance controllable attenuator stage.

Abstract: A convergence control system suited for use with high resolution color display monitors or color television receivers. The system includes both primary and secondary convergence controls having minimal interaction between them. An exemplified convergence control system comprises circuitry designed to develop output signal waveforms for implementing the following expression: ##EQU1## where X is a horizontal deflection-related signal input to the system, K is a static control for adjusting convergence at the center of the CRT screen, K3 and K4 are left and right side convergence controls, and K1 and K2 are secondary controls for correcting residual misconvergence--i.e., misconvergence at areas of the screen intermediate the areas converged using the K, K3 and K4 controls. A similar system is provided for providing vertical deflection-related convergence waveforms.

Abstract: A programmable attenuator includes MOS FET switches to electronically select a plurality of attenuation factors in a 1-2-5 step sequence. Such an attenuator is particularly suited for use in the input circuit of an oscilloscope.

Abstract: A capacitive goniometer comprises a plurality of like conductive annular sectors supported in mutually substantially coplanar relationship so as to define an axis which extends through the center of the annulus and is substantially perpendicular to the common plan of the sectors. A conductive member having a generally arc rate outer periphery is supported in spaced confronting relationship with the sectors with the outer periphery of the conductive member not extending substantially farther radially of the axis than the sectors, whereby an electrical signal applied to one of the sectors is capacitivity coupled to the conductive member.