Abstract: An automatic frequency control for causing a local oscillator to track the frequency of a transmitter such that the received echo of a transmitted pulse may be combined with the output of the local oscillator in a mixer to provide an intermediate frequency signal which is suitable for amplification, filtering and detection operations. The automatic frequency control includes an average frequency control loop for determining the average frequency of the local oscillator output signal, an electromechanical frequency transducer cooperating with a sample and hold circuit for providing a modulating signal to modulate the average frequency of the local oscillator output signal in response to the frequency of the next pulse to be provided by the transmitter, and a modulation gain control loop for controlling the gain of the modulating signal to compensate for variations in the transfer functions of the electromechanical frequency transducer and the sample and hold circuit.

Abstract: A turbine control system incorporating a speed monitoring system for generating an actual turbine speed measurement for control of turbine speed and load is disclosed. The speed monitoring system employs two identical speed channels each of both analog and digital form and a third channel of only analog form. The two identical speed channels of digital form and the third channel of analog form are coupled to a programmed digital computer based process controller for use in controlling turbine speed and load. The two identical speed channels of analog form and the third channel are coupled to an overspeed protection controller for use in preventing turbine overspeed. Within each controller, an identical channel is selected without preference to be used as the actual turbine speed measurement. A transfer between identical speed channels will only be performed if a malfunction is detected in that identical channel utilized as the actual turbine speed measurement.

Abstract: A self-triggering circuit for a gas-filled laser is disclosed. Electrical pulses which stimulate laser emission are applied to the laser cavity in response to an electrical energy change in the laser charging circuit when ionizing radiation is injected into the laser cavity. A semiconductor device of the type responsive to dv/dt, or of the type responsive to di/dt, is used as the self-triggering switch.

Abstract: An acousto-electric device provides a memory for a reference signal and provides for the convolution or correlation of input signals with the reference signal. The reference signal is transduced onto a piezoelectric surface to establish an electric field which determines the transfer and recombination of minority carriers across the p-n junction matrix of an adjacent semiconductor thereby creating a space-charge region in the semiconductor which is a spatial replication of the reference signal. The signal may be recovered in relation to the amplitude modulation of a carrier signal. For correlation or convolution of the reference signal with input signals, the input signals are provided to first or second terminals respectively and transduced onto the piezoelectric surface to produce electric fields which interact with the space-charge region of the stored reference signal to provide a product current whose integration comprises the correlation or convolution output.

Abstract: A CCD focal plane processor having a plurality of columns of individual sensor elements with plural sensor elements per column. The structure includes plural CCD shift registers corresponding to the number of columns of sensors, each CCD shift register including a pair of stages corresponding to each of the element sensors of the corresponding column of the array. Two "snapshots" of the scene are taken at time-displaced intervals and are compared to detect differences therebetween to eliminate background, or unchanging scene content. The individual sensors provide outputs which are injected into the .alpha. stages of the corresponding paired shift register stages of each CCD shift register in a first time interval corresponding to the first "snapshot". The resulting charge packets in the first (.alpha.) stages then are advanced to the second (.beta.) stages of each shift register pair. The second "snapshot" corresponds to injecting a second signal into the .alpha. stages of the plurality of pairs of .alpha.

Abstract: An amplitude stabilized power amplifier having a power splitter for dividing the power of an input signal into a predetermined number of channels, a plurality of amplifier modules for amplifying the power of each of the channels divided by the power splitter, and a power combiner for combining the amplified power signals to provide an amplified output signal. One of the channels of the power splitter is provided with a voltage controlled phase shifter whose phase shift is controlled by an operational amplifier which is responsive to a reference voltage and to the amplified output signal of the power combiner such that the signal in the channel provided with the phase shifter operates to limit the efficiency of the power combiner to maintain a power combiner output signal of constant power with respect to the reference voltage.

Abstract: A method and system for simulating the dynamic real-time operation of a nuclear power plant wherein a plurality of remote control devices provide input data to a digital computer to calculate physical values corresponding to plant operation to operate indicating devices for monitoring the physical operation of the plant.The simulation includes an electrical network calculation technique for solving a complex fluid flow network whereby non-linearity is applied by coefficient variation at subsequent time steps. Several engineered safeguards systems, including the accumulator system is disclosed. The safety injection system simulation is further characterized by a different network for each path that can be utilized in operation. The residual heat removal system is modeled to provide a path through each of the heat exchangers including the bypass around pumps for warming up pumps during start-up.

Abstract: A multiplexed filter bank having a digital by analog multiplier for weighting sampled input signals by digital constants is disclosed. The digital constants are stored and sequenced to the multiplier by a programmable read only memory.

Abstract: An intermediate-band, low-transient crystal filter utilizing standard components. The filter is characterized by improved response and temperature stability and a size which is smaller than presently used LC filters, helical filters and wide-band crystal filters. This is achieved by an unusual partitioning of a low-pass prototype ladder network which yields a cascade of symmetric lattice sections and, hence, a realizable crystal filter. The cascade is composed of only two fundamental sections.

Abstract: A high speed, high power, four layer, two-terminal silicon diode switch or thyristor designed to be fired by dV/dt induced current is disclosed. The device includes a shunted main cathode emitter, and an auxiliary cathode emitter centrally of the main cathode emitter. The auxiliary cathode emitter is so dimensioned that it is deeper than the main cathode emitter; and the product of (1) the capacitance of the central forward blocking PN junction within the confines of the outer edge of the auxiliary cathode emitter, and (2) the effective radial resistance of the cathode base beneath the auxiliary cathode, and (3) the rate of application of the firing voltage on the anode dV/dt, is at least equal to seven tenths of a volt.

Abstract: A video tracker for controlling the scanning of a sensor in an electro-optical tracking system in which the track point for the sensor is determined by balancing a volume signal from a first half of the track window with a volume signal from the second half of the track window in both horizontal and vertical directions of the track window to provide azimuth and elevation error signals. The volume signal for each half of the track window is determined by the product of the area of the corresponding half of the track window and the amplitude of the average linear video signal within that portion of the track window. Further, a multiplexed, time domain multiplier compares the gain of the azimuth and elevation error signals in successive fields of the sensor to normalize the gain of the azimuth and elevation error signals with respect to the displacement of the volumetric centroid of the target from the center of the track window.

Abstract: A dual gate MNOS memory transistor is disclosed. The transistor includes drain and source regions of a first conductivity type formed in a substrate of a second conductivity type. The region of the substrate between the drain and source regions forms the channel of the transistor. First and second insulating layers forming a charged trapping structure overlie the channel region. A first gate having a width less than the width of the channel overlies the central portion of the channel region. A second gate, insulated from the first gate, overlies the first gate and the remainder of the channel region. The threshold voltage of the transistor is shifted by selectively biasing the gates and the substrate. High and low threshold voltage states are used to represent the two values of a digital signal.

Abstract: A balanced circuit for IMPATT amplifiers and oscillators, which includes at least one pair of anti-series connected matched avalanche diodes electrically connected to the junction of a balanced and an unbalanced transmission line is disclosed. The diodes which are pumped by a large-signal input, are d-c biased to operate in the avalanche condition. A parametrically generated pair of unwanted idler frequencies are separated so that one component of the parametric-pair flows in the balanced line, and the other component flows in the unbalanced line. A central branch of the unbalanced line portion is resistively loaded to overcome the parametrically induced negative resistance of the diodes operating in the avalanche condition, and to suppress all incipient unwanted parametrically generated frequencies. The resistance loading, which is frequency independent, has little effect on the impedance presented to the diodes at the large-signal frequency.

Abstract: A noise generator that is responsive to digital noise quality and noise modulation input signals to provide a controller noise signal to a voltage controlled oscillator. The noise generator adds a center frequency input signal, a weighted random noise signal, and a weighted wobbulated waveform signal to obtain a controlled digital noise signal and converts this noise signal from digital form to analog form to provide a noise generator output signal that controls the voltage controlled oscillator. The center frequency and modulation of the noise generator output signal spectrum are determined by the center frequency and weighted wobbulated waveform signals, respectively, and the range of the output signal spectrum is determined by the weighting of the random noise signal. A ramp input signal, which is converted from digital to analog form, is integrated and added to the noise generator output signal to further define the quality and range of the output signal spectrum.

Abstract: A system for detecting the failure of steam inlet valves to respond properly to their respective control signals, is disclosed. The detection of such a contingency provides an appropriate indication, and also initiates a transfer to single valve operation when operating in the sequential valve mode. The system provides for indicating and/or transferring to single valve operations only after the contingency has been detected for a predetermined interval to compensate for the velocity limiting characteristics of the valve actuators.

Abstract: Unnecessary fast valving action for load loss protection in a steam turbine generator system induced by partial transducer failure is minimized by the disclosedmethods and apparatus. Upon the occurrence of a mismatch between reheat pressure and electrical output, the interceptor valve is closed momentarily to interrupt the flow of steam to the low-pressure turbine and prevent overspeed. The valve cannot be closed again for a predetermined interval. If the mismatch is not corrected by the one fast valving action, a transducer has failed and further closing of the interceptor valve, except for a full load loss, is precluded until corrective action is taken. The faulty transducer is singled-out by comparing one of the transducer signals with the impulse pressure which is also an indication of the actual operating level of the turbine.

Abstract: A phased array radar for providing a beam cluster whose average direction is determined by phase shifters associated with each antenna radiating element, and whose illumination function is determined by the phase and amplitude provided to subarrays of randomly agglomerated radiating elements which provide an aperiodic illumination error function that substantially reduces the grating lobes of the antenna pattern.

Abstract: An electronic system to monitor the performance of a pneumatic impact forming tool is disclosed. A signal is generated in real time representing the actuating pressure of the pneumatic tool. Electronic functions operate on the real time pressure signal over a predetermined time portion of each work cycle of the pneumatic tool to generate signals representative of the energy and friction developed in the pneumatic tool during the predetermined time portions of one or more work cycles. The electronic system additionally provides a count of the number of work cycles generated by the pneumatic tool during operation thereof.

Abstract: Improved low frequency electro-acoustic transducer apparatus of the type employing two piezoelectrically driven flexure discs mounted at the ends of a short cylindrical housing containing an acoustic mismatch fluid, is provided. The piezoelectrically driven flexure discs are constructed as assemblies having a plurality of concentric piezoelectric laminar sandwich units to excite the flexure discs. By individually electrically exciting the concentric sandwich structures through band-pass filters and a selective interconnection network, the flexure discs function with a plurality of resonant frequencies of flexing to provide broad band and efficient operation.

Abstract: A bistatic radar system for detecting the presence of a slowly moving target by the use of an arrangement which provides a reduction in the frequency spread of the reflected clutter energy. A radar transmitter and a radar receiver are located aboard separate aircraft which fly with a predetermined speed and direction about the target area. The speed and direction of the two aircraft are such that the angular velocities of the aircraft about the target area are substantially equal and opposite. This arrangement reduces the spread of the reflected clutter energy caused by motion of the radar transmitter and receiver relative to the target area. The radar return signals are filtered and processed to determine when a signal is present which has been shifted in frequency due to the motion of the moving target. In one embodiment, the two aircraft fly directly toward each other at the same speed. In another embodiment, the two aircraft fly directly away from each other at the same speed.