Abstract: A microwave cavity oscillator comprises a waveguide blocked at both ends, an active device enclosed in the waveguide and a dielectric powder or other fluid filling the remaining space in the waveguide. The microwave cavity oscillator is useful, for example, as in a discontinuity detector system.

Abstract: A portable low-output-level generator producing simultaneous audio, ultrasonic and RF noise for the test and demonstration of instruments designed to locate electrical interference, for demonstration of the broad frequency spectrum of electrical noise radiation, for antenna tests, to test the EMI susceptibility of electronic equipment, and to illustrate the effects of said noise on TV and radio receivers. This generator is enclosed in a housing and communicates audio and ultrasonic sounds to the observer via a vibrating diaphragm mounted on the face of the housing, with means provided to attenuate the audio sounds relative to the ultrasonic, and this generator radiates RF from a retractable antenna mounted on and extending outward from the housing.

Abstract: A variable frequency oscillator includes a RAM which stores a frequency setting data and provides a frequency control data, a VCO circuit which provides an oscillation output having a frequency which is defined by the contents of the frequency control data, a reference oscillator which provides a reference signal having a given frequency and phase, a phase comparator which detects the phase difference between the reference signal and a comparison signal corresponding to the oscillation output, and a logic circuit which combines the frequency control data with a phase data and provides the frequency setting data. The phase comparator provides the phase data whose contents indicate +1 if the phase of the comparison signal is delayed from the phase of the reference signal, indicate -1 if the phase of the comparison signal is advanced to the phase of the reference signal, and indicate 0 if the phase of the comparison signal matches with the phase of the reference signal.

Abstract: A phase synchronization circuit of a phase lock loop having a phase comparator, a loop filter or a low-pass filter and a voltage controlled oscillator controlled by output of said loop filter has been improved by a phase comparator having the hysterisis characteristics in which one of a pair of output levels is provided for each input phase difference according to phase error direction, except in the vicinity of a stable point of phase.

Abstract: An optical system transmits and reflects a laser beam along a common optical path between a laser generator and the target area on a workpiece. Illuminating light is transmitted along a portion of the optical path to the workpiece and is reflected therefrom to form an image of the target area projected onto a display screen. The reflected laser beam is focused at a detection point to monitor etch rate while the illuminating light is reflected adjacent thereto from the optical path to provide a visual indication of the laser beam locations on the workpiece corresponding to the image being simultaneously displayed.

Abstract: An electronic dither compensator for a ring laser gyroscope uses a velocity pickoff to eliminate the need for a differentiator following a displacement pick off in order to get a rate signal. The dither pickoff is converted, in a voltage to frequency converter, to a pulse train which is synchronized with the pulse train of the uncompensated input from the gyro detector. An automatic gain control with an amplitude control loop is provided. The pulses from the voltage-to-frequency converter and uncompensated inputs are synchronized and summed and differenced as selected by means of logic to produce gyro output pulses free from the effects of dither rate.

Abstract: A temperature-compensated oscillator avoids noise heretofore caused by unduly high signal level changes of a control voltage resulting from sensed temperature changes. This is done by reducing the high level changes into a plurality of relatively low level changes which produce a cumulative effect comparable to the high level effect. The many low level changes do not produce reactions which are abrupt enough to cause noise, especially a phase modulation or frequency modulation noise.

Abstract: An apparatus and method is disclosed that provides a random data generator that is less susceptible to error sources resulting from negative feedback biasing. This invention utilizes a shift register and a multiplexer, controlled by the shift register, to provide the feedback to an amplifier. This improves the correlation between the present data output bit and the following bit.

Abstract: The interior of a metal housing is divided by a dielectric substrate into two compartments. At least one of the compartments is kept air-tight. The substrate carries thereon a semiconductor active element chip for oscillation within the air-tight compartment and a dielectric resonator within the other compartment. The chip and the resonator, electromagnetically coupled with the chip, constitute a microwave oscillator whose oscillation frequency can be stabilized. A metal screw is threaded into that wall of the housing which defines the other compartment in a predetermined positional relationship to the resonator. The metal screw is rotatable to vary the distance between the screw and the resonator and, thereby, the oscillation frequency.

Abstract: Disclosed is a circuit providing a controllable effective resistance which comprises of transistor means that provides current at an input node responsive to an input voltage at the input node. The transistor means is coupled to a settable current source which operates to control the effective value of the controllable effective resistance. The invention also includes a filter which employs the controllable effective resistance to vary the breakpoint frequency of the filter. Also, a phase-locked loop apparatus employing the filter is disclosed.

Abstract: A quadrature detector circuit for demodulating frequency modulated information is provided that is particularly designed for use in television receive only (TVRO) satellite communication video receivers. The bandwidth restrictions of conventional quadrature detector circuits are eliminated by substituting a simple ferrite bead for the usual parallel capacitor, inductor, resistor combination heretofore required in quadrature detectors. The quadrature detector hereof produces a higher level of video output, improved linearity, and better selectivity, as compared to conventional quadrature detector circuits. Moreover, the quadrature detector hereof reduces circuit complexity, and decreases material costs and production time.

Abstract: A frequency modulation detection arrangement comprises an FM detector and an injection-locked frequency divider arranged for receiving a radio signal and for providing a frequency divided radio signal in response thereto. The FM detector is coupled with the injection-locked frequency divider for receiving the frequency divided radio signal therefrom and for producing a signal indicative of the information content of the modulating wave of the radio signal.

Abstract: A crystal oscillator circuit that is temperature compensated over a broad temperature range has a crystal oscillator, a reactance compensation circuit for providing temperature compensation at low temperatures, and a control voltage-generating circuit for providing temperature compensation at high temperatures. The reactance compensation circuit includes the parallel combination of a thermistor and a variable-capacitance diode, and this parallel combination is connected in series with the crystal oscillator. The control voltage-generating circuit includes a thermistor and transistors and applies a voltage corresponding to the ambient temperature to the variable-capacitance diode of the reactance compensation circuit.

Abstract: A receiver for receiving and demodulating FSK modulated data signals has improved sensitivity over substantial frequency offsets between the transmitter and receiver local oscillator, and low spurious electromagnetic radiation. A quadrature coupler splits the received signal into in-phase and quadrature phase signals which are then mixed down to baseband, filtered, and limited. An RC circuit at the output of a four flip flop demodulator averages the flip flop output signals. A voltage comparator outputs a logical 1 if the voltage at the output of the RC averaging circuit is greater than one-half the supply voltage; otherwise the comparator outputs a logical zero.

Abstract: The present invention consists of an apparatus comprising a phase locked loop and a frequency loop having a discriminator and a disable. The disable is used to electrically disconnect the frequency loop from the phase locked loop when the phase of the output from the voltage controlled oscillator is within a preset range of the incoming signal. The disable acts to provide an adjusting voltage signal, set by the discriminator, to the phase locked loop when the output and input signal phases are out of the preset range. When they are within the preset range the disable outputs a zero voltage regardless of the input from the discriminator.

Abstract: An oscillator-mixer arrangement including a dual-gate field effect transistor of the Schottky type for supplying an intermediate frequency output signal. The output signal is obtained by subtractively mixing a high frequency input signal and a signal produced in the arrangement. The input signal is applied to the first gate electrode (G.sub.1), the produced signal is controlled by the second gate electrode (G.sub.2), and the output signal is recovered at the drain electrode (D), while the source electrode (S) is directly connected to ground. A micro-strip line having a characteristic impedance Z.sub.O which is electromagnetically coupled to a dielectric resonator and loaded by an impedance (Z.sub.O) is connected to the second gate electrode (G.sub.2). The arrangement is intended to be included in a receiver front end assembly for very high frequency waves, typically of a frequency of 12 GHz, used for broadcasting radio-television programs by artificial satellites.

Abstract: An inverter (100) receives a DC voltage and generates therefrom a square wave output signal. The inverter includes an output transformer (T3) and a saturable core transformer (T4). The saturable core transformer (T4) provides base current for a first transistor (Q3) and a second transistor (Q4). The first transistor (Q3) and the second transistor (Q4) alternatively turn on and off, causing a square wave to appear across the secondary winding of the output transformer (T3). The primary winding of the output transformer is coupled to the collectors of the first and second transistors via a pair of windings (L10, L11) magnetically coupled to the saturable transformer (T4). A pair of diodes (D4, D5) are provided to prevent the output leads of primary windings of the output transformer (T3) from dropping below ground potential.

Abstract: A reference signal from a reference signal source is supplied to a frequency transformer and a side band signal generator. The frequency transformer is formed mainly by up-converters and produces a frequency m times as high as the frequency f.sub.s of the reference signal. The side band signal generator outputs signals of base and harmonic frequencies f.sub.s, 2f.sub.s, 3f.sub.s, . . . and nf.sub.s (where n is less than m) and produces less phase noise than does the frequency transformer. The outputs of the frequency transformer and the side band signal generator are frequency mixed by a frequency mixer, and one frequency component in the frequency-mixed output is selected by a variable filter.

Abstract: A synchronization circuit for a free-running oscillator, in which a multi-tapped delay line provides delayed outputs incrementally spaced throughout the period and at the same frequency as the oscillator. That delayed signal closest in time to a reference signal is selected as the output signal, synchronized to the reference signal.

Abstract: An oscillator comprises an amplifier with a feedback loop from the output to the input thereof, the feedback loop including a resonator such as a crystal providing oscillation of the amplifier at a predetermined frequency. A balanced modulator coupled to the amplifier generates a voltage varying at the same frequency, said voltage being selectably variable in amplitude from zero upward either in phase with the amplifier or 180 degrees out of phase therewith. The voltage is selectably inserted into the feedback loop 90 degrees out of phase with the output of the amplifier, whereby, when it is inserted, the frequency of oscillation of the amplifier varies from the predetermined frequency in direction depending upon the phase relationship of the amplifier and voltage and in amount upon the amplitude of the voltage.