Abstract: A programmable range recognizer produces a recognition signal whenever a digital word occurs within a specified closed range of digital words. Such a programmable range recognizer is useful for triggering or data qualification in a logic state analyzer. The range recognizer comprises a random-access memory divided into a plurality of sections, each for decoding a corresponding byte of the digital word, and a combination logic circuit for combining decoded bits to produce a recognition output.

Abstract: This application discloses a linear class B transconductance power amplifier suited for use in driving an inductive load, such as a convergence control coil for a color television receiver or video monitor. A preferred form of the amplifier includes a first pair of transistors having their emitters connected together and to a reference potential, their collectors being connected together and to a voltage source; and a second pair of transistors connected to the bases of the first pair of transistors and connected together in the form of a differential amplifier. The amplifier circuit operates as a noninverting operational amplifier when an input voltage has a positive polarity, and it operates as an inverting operational amplifier when the input voltage has a negative polarity.

Abstract: A digital time base for producing sample clock pulses is provided with a control circuit to permit coherent switching from one sample rate to another. A plurality of predetermined sampling rates and number of samples to be acquired at each rate are stored in a memory. The predetermined sampling rates provide count moduli to a counter which divides the frequency of a base clock in accordance therewith to produce the actual sample clock pulses. A counter is provided to count the sample clock pulses, and when the desired number of pulses are generated, a next succeeding sampling rate and number of samples to be acquired are accessed from the memory. The rate switching to change the count modulus takes place between last sample clock pulse generated for a particular sampling rate and the next succeeding base clock pulse so that such switching is coherent.

Abstract: A buffer amplifier circuit is provided in which the effects of power supply noise is substantially reduced while contemporaneously exhibiting the attributes of low thermal distortion and high linearity. The amplifier comprises a source follower input stage which contains additional devices to absorb power supply variations, and an emitter follower output stage. A constant-current bias network includes means for bootstrapping the gate-to-drain capacitance of the input source follower.

Abstract: A differential shunt feedback amplifier includes dual shunt feedback paths, with an emitter follower in each feedback path to provide a low impedance output with a well-defined gain. A common-mode current generator responsive to only the common-mode component of an input signal generates a current which offsets base current changes in the emitter followers caused by the common-mode component. The circuit is well suited for either push-pull or single-ended input operation over a wide range of frequencies.

Abstract: A power supply circuit comprises a main transformer having a primary winding and a secondary winding, a series resonance circuit coupled to the primary winding of the main transformer, and a switching circuit for alternately supplying DC power to the series resonance circuit and discharging the energy stored therein. A current protection circuit controls the switching circuit in dependence upon the current in the switching circuit and a voltage protection circuit controls the switching circuit in dependence upon the voltage of the secondary winding of the main transformer.

Abstract: A D.C. stabilization circuit is provided for a follower-type amplifier in which a correction current is generated to maintain a constant operating point of the follower device. A blocking capacitor between a signal source and the follower device permits the bias voltage to self adjust. In a preferred embodiment, the correction current is generated by a transconductance amplifier which compares the output voltage with a signal input voltage, and the correction current is connected directly to the junction of the blocking capacitor and the input of the follower device. The follower device may suitably be a field-effect transistor, a bipolar transistor, or a multi-stage follower composed of both types of devices.

Abstract: A programmable delay circuit comprises input and output multiplexers, a delay device provided between the multiplexers, and a negative feedback path. When the input multiplexer selects an input logic signal, the delay time is controlled by the output multiplexer. When the input multiplexer selects the feedback path, the delay circuit acts as a ring oscillator for generating a square-wave signal whose period is twice the selected delay time. Additional delay devices and multiplexers may be provided between the input and output multiplexers.

Abstract: A cathode-ray tube including feedback means capable of producing a feedback signal indicative of the position, in at least two dimensions, of a scanning electron beam. The feedback means comprises a plurality of feedback elements disposed at selected locations within the tube enclosure. With a shadow-mask type CRT, the elements are formed on the gun-side surface of the shadow mask itself. With other kinds of CRT's, the elements are formed either on an interior supporting member or on the interior surface of the display medium. In one embodiment, the elements are formed of a phosphorescent material. In other embodiments, the elements are formed of materials capable of producing, upon excitation by a scanning electron beam, signals of visual or electrical character. The signals thus produced may be employed in a closed-loop correction system to accomplish automatic convergence and/or geometric adjustment of a displayed image.

Abstract: An electronic filter device comprises a high frequency section and a low frequency section. The high frequency section has an input coupling loop connected to an input connection of the filter device, and a gyromagnetic resonance element. The low frequency section comprises at least one inductor and at least one capacitor connected to the input coupling loop of the high frequency section. The two sections of the filter device have separate output connections.

Abstract: A triangle waveform generator is provided with a compensation network to eliminate the effects of frequency and amplitude errors caused by switching-control loop delays of the system. This is achieved by causing early switching of an amplitude-limit sensing detector so that the generated triangle waveform reverses polarity at the correct level. The compensation network may be implemented to accommodate independent ramp rates.

Abstract: An emulator control sequencer comprises a programmable state machine which passively monitors the data bus of an emulator microprocessor, extracts certain information indicative of internal processor behavior, such as when the next opcode fetch will occur, as well as detecting current opcodes, and generates control signals for the emulator.

Abstract: A digital dither generator is described which produces a series of discrete analog values which remain constant for each repetition of a signal being digitized. These analog values are summed with the analog input value being digitized. The dither states exhibit two useful characteristics; a bit-reversal scheme in which a sequence of dither values is used to progressively maximize the resolution of the digitizer and a technique of offsetting the values by a known amount to statistically improve digitizer accuracy.

Abstract: A one-piece snap-in spacing device and support member for circuit boards is provided with a tapered pin axially disposed at each end of a spacer body to fit snugly into corresponding holes positioned near the edges of a pair of circuit boards. Integrally molded with the spacer body is a pair of clips each having a ramped nib to engage and grip the edge of a circuit board with a snapping action. The spacing device is provided with a flat surface for mounting to a chassis.

Abstract: A system for recording graphic information, stored in digital form in a data memory, on a moving record medium comprises a controller which is responsive to the travel rate of the moving record medium to supply digital signals from the data memory to a recording member in synchronization with the movement of the record medium.

Abstract: The drive circuit of the present invention is characterized by a second amplifier for amplifying the video signal which controls the voltage at the control grid G.sub.1 of the cathode-ray tube. This second amplifier has a wider bandwidth than the similar amplifiers of the prior art. It therefore generates a signal having a lower dynamic range than the dynamic ranges of the output signals associated with the similar amplifiers of the prior art. To compensate for the lower dynamic range of the output signal generated by the second amplifier, the drive circuit of the present invention measures the current in the cathode of the cathode-ray tube, converts this measured current into a voltage, stores the voltage in a capacitance, and amplifies the stored voltage in a fourth amplifier. The fourth amplifier generates a signal having a wider dynamic range than the dynamic range of second amplifier. The output of the fourth amplifier is combined with the output of the second amplifier.

Abstract: A signal sampling system includes a combined digital and analog acquisition time base for accurately sampling and displaying an extremely short duration electrical event superimposed on a long time duration signal. The signal sampling system of the present invention is intended for use in stimulus-response situations, and both stimulus and response signals are synchronized with the clock of the digital portion of the time base. The system may be operated under microprocessor control, providing both flexibility and programmability, in turn permitting not only acquisition of waveforms that start and stop at arbitrary points with extreme precision, but signal averaging or smoothing as well.

Abstract: An output monitoring method and apparatus is provided for a programmable power supply in which the supply produces one of a programmed voltage or current value and the appropriate value is displayed on a single display device.

Abstract: A log-conformance correction circuit for a prototype circuit employing semiconductor devices comprises a quad of devices with voltage drops arranged in series, and currents or current densities driven such that the logarithmic components in the voltage drops sum to zero while log-conformance error components are produced. A correction quad suitably may comprise two pairs of semiconductor devices in which the current densities in one pair are cross-proportional with the current densities of the other pair, and of a different magnitude to establish a current density ratio between the pairs. The log-conformance error components which are generated by the correction quad are inserted into the prototype circuit to cancel log-conformance error therefrom.

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.