Abstract: A high-precision amplifier employs a feed-forward technique to provide a first order correction of amplifier distortion. A second amplifier is utilized to sense the base-to-emitter distortion of a main amplifier and develop an error output which is injected into an output node to provide cancellation of distortion from the output of the main amplifier. The feed-forward distortion-correction technique is particularly applicable to high-precision wideband differential amplifiers; however, the technique may be used in other amplifiers as well.

Abstract: An amplifier includes a network which generates additional output current for driving a substantially capacitive load as the frequency of an input signal is increased. The network comprises a plurality of rate discriminators which activate additional current sources at predetermined frequencies.

Abstract: A pulse width normalizer circuit incorporates a delay line to ensure a predetermined minimum pulse width output when input pulses become narrower than the predetermined minimum width. One output and one input of a differential amplifier are coupled to a delay line having a predetermined length and a shorted opposite end. An input pulse is applied to the other input of the differential amplifier, causing the outputs to switch to thereby produce an output pulse. The differential amplifier remains latched for the time it takes the leading edge of the output pulse to propagate down the delay line and back.

Abstract: A feedbeside correction circuit for correcting errors in the frequency response of a wideband amplifier includes a network which models the physical distortion-producing mechanisms of the amplifier semiconductor pn junctions. An input signal is applied simultaneously to the amplifier and to the feedbeside circuit. The feedbeside circuit produces a correction signal which is applied to a summing node and subtracted from the amplifier signal so that the amplifier output is substantially error free. The circuit may be used both for single-ended and differential inputs.

Abstract: A Constant Velocity Vector Generator is disclosed for connecting X, Y coordinate points of a rectangular coordinate display system. A pair of absolute value amplifier circuits, a square-root-of-the-sum-of-the-squares circuit, a pair of dividers, and a pair of integrators are employed to convert simultaneous .DELTA.X and .DELTA.Y step voltages to ramp voltage pairs which are applied to appropriate X and Y deflection circuits of a graphic display device to produce straight-line traces whose velocities are constant for all vectors regardless of magnitude (line length) or direction (angle). Each vector may be drawn to any length or direction, immediately after which new data may be applied to the vector generator to initiate a new vector whose origin is the end point of the preceding vector. Such a system is particularly applicable to computer-drawn displays. The vector generating circuits are suitable for realization in a monolithic integrated circuit.

Abstract: An automatic trigger circuit for an oscilloscope includes a clock driven up-down counter and a digital-to-analog converter to automatically seek a suitable triggering level in the absence of an input triggering signal. When such level is established, the associated sweep generator is triggered, producing a display trace. Thereafter,the sweep generator is cyclically retriggered as the sweep "free runs.

Abstract: A Constant Velocity Vector Generator is disclosed for connecting X, Y coordinate points of a rectangular coordinate display system. A pair of absolute value amplifier circuits, a square-root-of-the-sum-of-the-squares circuit, a pair of dividers, and a pair of integrators are employed to convert simultaneous .DELTA.X and .DELTA.Y step voltages to ramp voltage pairs which are applied to appropriate X and Y deflection circuits of a graphic display device to produce straight-line traces whose velocities are constant for all vectors regardless of magnitude (line length) or direction (angle). Each vector may be drawn to any length or direction, immediately after which new data may be applied to the vector generator to initiate a new vector whose origin is the end point of the preceding vector. Such a system is particularly applicable to computer-drawn displays. The vector generating circuits are suitable for realization in a monolithic integrated circuit.

Abstract: A high-impedance programmable attenuator utilizing field-effect transistor (FET) switching in both the high-impedance and low-impedance sections. In the high-impedance section, hybrid passive attenuator elements are employed to provide attenuation of electrical signals, and both series and shunt forms of active switching are employed to align the appropriate signal paths. The low-impedance amplifier section includes a FET-switched resistive network.

Abstract: A pair of clock driven voltage comparators are arranged in a master-slave configuration so that voltage comparisons are made only on a clock edge and the output is held valid over the entire clock period. Each comparator stage includes a latch to lock the comparator output in the logical state it was in when the latch was enabled.

Abstract: A pulse peak detector for producing a D.C. voltage level corresponding to the peak amplitude of an input signal. A differential comparator is utilized to compare the input signal to the output level, and to activate a control circuit when the peak amplitude of such input signal exceeds the output voltage. The control circuit includes a current source which operates for a predetermined resettable time interval to provide a charging current path for a storage capacitor. An emitter follower is disposed between the storage capacitor and the system output to isolate the capacitor from any output loading. For short-duration repetitive input pulses, for example, 10 nanoseconds or less, a latch circuit insures activation of the timing circuit.

Abstract: An improved delayed sweep system is disclosed for an oscilloscope having main and delayed sweeps. A trigger pickoff circuit has means for providing a pair of pre-selected trigger pickoff points on the delaying sweep so that delayed sweeps may be generated in accordance with the two points selected. An alternating display mode facilitates presentation of the delaying sweep and both delayed sweeps in a single display, with the relative time positions of both delayed sweeps appearing on the delaying sweep as a pair of intensified zones. Either delay time measurement between the sweep start and a point of interest on the display, or differential time measurement between two points of interest on the display may be made. Voltages proportional to the selected time measurement may be applied to a properly scaled digital voltmeter to provide a direct readout in units of time.

Abstract: A simplified keyboard for a terminal device, calculator, or the like, in which each key is sequentially scanned and parallel key code data is sent to an entry register. A pair of flip-flops in combination with firmware ascertain that only valid key code data is sent to the entry register for utilization by the system, providing double entry and key bounce protection. The firmware further provides N-key rollover and auto repeat with a variable repeat rate, and expands the keyboard from a single-mode to an eight-mode capability.

Abstract: A slewed-pulse display is provided for calibrating the time-base axis of an oscilloscope. In a repetitive-sweep display, the leading edges of incrementally delayed successive pulses are slewed across the display screen. Timing and linearity adjustments may be made in the time-base generator circuits so that a leading edge of a pulse is aligned with each vertically scribed graticule line overlaying the display area.

Abstract: A system for indicating the sweep rate of an oscilloscope time base. A counter is enabled by a sweep gate signal to permit clock pulses having a predetermined repetition rate to be counted during the time a sweep-driving ramp waveform is generated. The count output, which is proportional to the length of a time-base sweep, is decoded to generate specific control signals indicative of the sweep rate thereof. The control signals may then be used by a utilization means to provide a visual readout of the time-base sweep rate or to provide auto ranging for a digital voltmeter scaled in time units for time interval measurements.

Abstract: A wideband differential amplifier comprises a pair of differentially connected control devices, for example transistors, having a pair of semiconductor junction input devices coupled thereto for receiving complementary input currents. The input devices exhibit logarithmic characteristics substantially compensating for nonlinear properties of the pair of differentially connected control devices, whereby a linear rather than a nonlinear amplified current output is produced. Multipliers, cascaded amplifiers, and other useful circuit configurations are provided.

Abstract: A circuit is provided for generating signals proportional to distortion of a square-wave reference signal caused by the impedance mismatch of an attenuator probe and the input impedance of an electronic instrument. The generated signals are utilized to control an indicator device and thereby provide an indication of the mismatch as well as proper compensation of the probe.

Abstract: An improved electronic sampling circuit combines the merits of a high-efficiency sampling system with the DC stability of the more standard feedback sampling system. The stabilized high-efficiency sampling system is very useful for sampling high-speed events at a fixed repetition rate, such as occurs in time-domain reflectometry applications, as well as for sampling at very low trigger rates or at varying trigger rates such as are found in general-purpose sampling equipment. The high-efficiency characteristic of this sampling system is obtained by adjusting the effective memory capacitance of a sampling gate to provide unity dot response. The DC stability characteristic is maintained by a resistive feedback loop from the system output to input.

Abstract: A circuit to correct for pincushion distortion and defocusing in a cathode-ray tube having electromagnetic deflection systems is disclosed. The circuit, which may be realized in monolithic integrated-circuit form, performs a mathematical function to predistort the deflection signal for each axis by the amount necessary to provide an undistorted display. The circuit also provides a signal to correct for the defocusing that occurs at the edges of the screen. The circuit may be readily adapted for use with cathode-ray tubes having different diagonal deflection angles, and with either flat of curved faceplates, by changing the values of two resistors.

Abstract: An oscilloscope and a digital multimeter are combined in a single housing to provide a portable electronic measurement instrument wherein a substantial portion of circuitry is common to both measurement systems. A cathode-ray tube provides the display for both waveform and alpha-numeric information.

Abstract: A photometric monitoring device for detection and surveillance of objects entering and leaving a light field is provided wherein a monitored light source is compared with a reference light source in such a manner that abrupt or rapid changes in monitored light are detected and gradual changes are ignored. A first photo cell for monitoring a light source is coupled to the input of an operational amplifier having a feedback loop which includes a reference light source coupled to a second photocell. An RC network delays the reaction of the operational amplifier in balancing the voltage across both of said first and second photocells when abrupt changes occur, allowing a signal to be developed. Additional circuitry includes a comparator responsive to such developed signals which exceed predetermined limits, producing an output signal for use by a utilization device, such as a camera, recording device, alarm system, or the like.