Abstract: The invention is concerned with the detection of the presence of narrow pulses in an electrical signal such as that derived from a limited band width receiver. A first discriminator is provided for discriminating against pulses other than those having a ratio of amplitude to width characteristic of a desired narrow pulse. A second discriminator is provided for discriminating against pulses other than those having a width characteristic of a desired narrow pulse and a third discriminator is provided for discriminating against pulses other than those which have a symmetry characteristic of a desired narrow pulse. The input is applied to the first and second discriminators in parallel with the third discriminator arranged to be effective only for those pulses which have not been discriminated against by the first and second discriminators.

Abstract: Apparatus is disclosed for generating electrical pulses in response to rotation of a shaft. The apparatus incorporates an internal optical disc carried by a hub assembly attached to the operating shaft, with the hub assembly having a beveled bearing surface at one end thereof for engaging a similarly beveled surface of the apparatus housing, and biasing means for biasing the hub assembly toward said housing beveled surface to compensate for mechanical wear and to also minimize erratic movement of the optical disc. The combination of a light emitting diode and photo-transistor generate electrical signals in response to the blocking and transmitting of light through radially oriented opaque segments of the disc during rotation. The light emitting diodes and photo-transistors are retained by receptacles which snap fit within cooperating apertures of the housing.

Abstract: User control apparatus for a system such as a television receiver having a plurality of user controllable functions such as channel, volume, brightness, contrast, color saturation and tint, includes a plurality of individual pushbuttons for changing respective functions in a first sense, e.g., "up" and a common pushbutton for changing all of the functions in a second sense, e.g., "down". Operation of one of the individual pushbuttons selects the function to be controlled and causes the function to be increased. Thereafter, operation of the common pushbutton causes the selected function to be decreased.

Abstract: In a high speed synchronizing circuit, the rising edge of an asynchronous input signal is used to set an input RS flip-flop. First and second latch registers monitor the input RS flip-flop. Each latch register generates a reset signal before a change in the logic level of the system clock for resetting the input RS flip-flop. The reset pulses are very narrow which enables the RS flip-flop to be quickly conditioned to receive the next asynchronous signal.

Abstract: Offset voltages of a precision rectifier circuit, buffer amplifiers, and an input comparator of a log converter are compensated for by charging a coupling capacitor to the combined total offset voltage of the apparatus. The charging is effected by causing the comparator to operate as a unity gain inverting amplifier during part of the operating cycle of the log converter when the comparator output signal is not used, so that the log converter operation is not adversely affected. During such charging the input of the precision rectifier circuit, to which the a.c. input signal is normally applied, is grounded. Throughout the charging and associated switching operations a capacitor of a smoothing filter connected following the precision rectifier circuit is disconnected from ground to isolate the smoothing filter output from ground and to prevent switching transients from affecting the charge of this capacitor.

Abstract: In a bias circuit including at least a pair of bipolar transistors interconnected to function as active loads, two junction field effect transistors are interconnected such that the source of one transistor is connected to the emitter of the first of the pair of bipolar transistors and the source of the second junction field effect transistor is connected to the emitter of the second of said bipolar transistors, and the gate electrodes of the first and second junction field effect transistors are electrically connected to each other and to the drain electrodes of both the first and second junction field effect transistors. Alternatively, the drain electrodes of the first and second junction field effect transistors are connected to a common bus and the gate electrodes are connected to a low impedance node.

Abstract: A multiplier circuit for controlling gain amplification of an electrical input signal responsively to a control signal comprises log conversion means for producing a log signal as a logarithmic function of the input signal, means for producing a multiplier signal as a function of the sum of the log signal and the control signal and antilog-conversion means for producing an antilog signal as an antilogarithmic function of the multiplied signal. The improvement is characterized by the log conversion means and antilog conversion means each including passive elements capable of exhibiting log-linear and antilog-linear transfer characteristics. The passive elements are preferably in the form of diode elements connected in a diode bridge.

Abstract: A logic driver circuit repowers signals in either direction along a line, without requiring any external direction-control signal. Two back-to-back driver halves each include a gate, an open-collector transmitter and a latch. The latch is connected to the gate and transmitter to prevent race conditions.

Abstract: A field effect transistor is used to short circuit the timing capacitor of a gaseous tube when power is interrupted or removed. The short circuiting of the timing capacitor prevents the residual capacitor charge from being added to a new charge after an interruption so that the early firing of the gaseous tube is avoided and damage is prevented.Because capacitor charging always starts at zero voltage when the field effect transistor is used, hysteresis, at low voltage outputs, from the gaseous tubes is greatly improved.

Abstract: An access circuit for use in a computer input-output channel. Retriggerable mono-stable multivibrators are used to provide access timing periods during which an input-output device can access a computer channel to the exclusion of other input-output devices.

Abstract: A sensor-integrator utilizes a light sensing diode directly connected to the inputs of an operational amplifier. The operational amplifier forms part of a dual-slope integrator and directly integrates the current generated by the light sensing diode thereby eliminating the need for preamplifiers and diode switching circuitry.

Abstract: An excitation circuit is disclosed which is responsive to a trigger signal to drive a capacitive load with a controllable high frequency pulse burst. The pulse burst takes the form of a multiple cycle output signal which has a selectively variable high voltage determined by the supply voltage of the circuit. The output signal replicates and is coherent with the trigger signal applied to the circuit. The latter signal thus determines the pulse width and signal duration, i.e. the number of cycles, of the output signal. The circuit is particularly adapted to provide a programmable burst excitation for driving an ultrasound transducer or the like.

Abstract: An electronic circuit which produces controlled rise and fall times with a sine-squared step pulse shape from rectangular input pulses is disclosed. The circuit uses the inherent nonlinear behavior of a bipolar transistor differential pair to shape the pulses and requires very little passive filtering. The output wave-shaped current may be developed across a resistor or fed to the input mode of a feedback amplifier.

Abstract: A variable frequency missing pulse detector includes a reference signal generator comprising a series connected frequency-to-voltage converter and voltage-to-frequency converter which produces a reference signal with a frequency proportional to the average frequency of a variable frequency source. A pulse generator generates test signal pulses from the source on a cycle-by-cycle basis. A logic circuit compares the reference and test signals and produces a warning signal when a test signal fails to occur during a full cycle of the reference signal.

Abstract: A method of monitoring the rate of change of a first signal which includes the steps of periodically sampling the first signal, generating a first reference signal which for each period differs from the sampled amplitude of the first signal by a predetermined amount, comparing the amplitudes of the first signal and of the first reference signal, and generating an output signal when the amplitude of the first signal crosses the amplitude of the first reference signal.The invention also provides apparatus for monitoring the rate of change of a first signal which comprises means periodically to sample the first signal, means to generate a first reference signal which for each period differs from the sampled amplitude of the first signal by a predetermined amount, and means to compare the amplitudes of the first signal and of the first reference signal and to generate an output signal when the amplitude of the first signal crosses the amplitude of the first reference signal.

Abstract: A product or multiplier circuit for use in an FM quadrature detector including a double-balanced differential amplifier having resistors disposed in the emitter circuits thereof. Product signals formed at collector junctions of the differential amplifier are amplified by a differential amplifier transistor pair having its emitter circuits fed by a current source and its collector circuits coupled to a current mirror circuit. By restricting the resistance values of the emitter circuit resistors of the double-balanced differential amplifier within a disclosed range, the distortion factor and signal-to-noise ratio of the circuit are improved.

Abstract: An integrated circuit having circuitry for clamping input terminals that remain unconnected after assembly into a system. A transistor is connected to clamp the input terminal to reference potential and provide regenerative feedback to a NAND circuit forming a latch which maintains the transistor on when the input terminal would otherwise be left floating. Alternatively, when the terminal is connected to supply potential, the transistor is maintained "off", precluding loss of power.

Abstract: A precision rectifier circuit includes two differential amplifiers each having a negative feedback path including a diode. Two pnp transistors have their base-emitter paths connected in parallel with the respective diodes and their collectors connected together and via an output resistor to ground. An a.c. signal to be rectified is applied to non-inverting inputs of the amplifiers, whose inverting inputs are interconnected via a resistor in series with a capacitor, to develop a unipolar output voltage across the output resistor. The capacitor renders the output voltage independent of input offset voltages of the amplifiers. The transistors can comprise Darlington-connected transistors to avoid the need for matching.

Abstract: A background subtractor circuit is disclosed for subtracting a preselected number of pulses from a train of input pulses. Switches are provided whereby the operator selects the background pulse rate, attributed to environmental factors, and wherein a train of background pulses are subtracted, at a preselected rate, from the incoming pulse train.

Abstract: A switching circuit for an alternating current line allows the voltage or rrent coupled from the line to a load circuit to be controlled. Control may be in response to changes in voltage or current coupled as a feedback signal from the load to a switching circuit in the line for applying or terminating alternating current line voltages. In an alternative embodiment a switching circuit is initiated at the time alternating current voltages are applied to a load and after a predetermined time interval the switching circuit operates to disconnect and lock out the alternating current voltage.