Abstract: In a particular embodiment, the invention is directed to a composite MMIC amplifier comprising a plurality of active devices (e.g., FET, HBT, HEMT) arranged on a semiconductor substrate and having inputs and outputs. A pair of input and output transmission lines are coupled in antiphase arrangement to corresponding inputs and outputs of alternate active devices. Each pair of input transmission lines has branched portions extending from a common polarized input terminal. Each branched portion of like polarity extends to a corresponding alternate input and output of an active device and crosses a branched portion of opposite polarity without interference. Impedance matching means is coupled across antiphase pairs of inputs and outputs of adjacent active devices and forms a virtual ground therebetween thereby simplifying the impedance matching circuit.

Abstract: An azimuth-stacked radar method and apparatus of the type typically used for surveillance employs a mechanically-rotating antenna comprising horizontal end-fed rows of antenna radiating elements with phase shifter control on each row together with a monopulse elevation manifold to generate an elevation sum and difference beam pair. Additionally, this radar employs a waveform comprising multiple subpulses at different frequencies with sufficient separation between the subpulses at each frequency to spread them in azimuth to form a beam cluster and employs mechanical antenna rotation and phase-responsive elevation scanning. The scanning is accomplished in a way that will permit advantageous avoidance of ground clutter and other uninteresting radar reflectors.

Abstract: An ultra low noise oscillator circuit including a crystal and having two outputs. At the two outputs, the signal is correlated and the noise outside of the crystal bandwidth is decorrelated. Summing the two outputs in a hybrid circuit significantly reduces oscillator phase noise by almost 3 dB. In addition, these outputs can be used to perform a single oscillator noise test on the oscillator or crystal.

Abstract: A broad band multimode seeker system for a missile includes a wide band phased array transmitter/receiver unit incorporating a wafer scale phased array device with a bandwidth of about 2 GHz to 35 GHz. A multimode intermediate frequency unit selectively generates radar and jamming waveforms and measures parameters of reflected radar and external emissions of RF energy. A guidance processor manages the front end assets for selective active or semiactive radar searching and tracking, and simultaneous searching for, tracking of, homing on, and applying a selection of electronic countermeasures to, multiple defensive radars. Confirmation of an assigned target is made through correlation of received RF signals with libraries of expected defensive system parameters and high resolution target profiles and preloaded target geographical coordinates.

Abstract: This application discloses a system that optimizes a neural network by generating all of the discrete weights for a given neural node by creating a normalized weight vector for each possible weight combination. The normalized vectors for each node define the weight space for that node. This complete set of weight vectors for each node is searched using a direct search method during the learning phase to optimize the network. The search evaluates a node cost function to determine a base point from which a pattern more within the weight space is made. Around the pattern mode point exploratory moves are made which are cost function evaluated. The pattern move is performed by eliminating from the search vectors with lower commonality.

Abstract: The total periodically induced vibratory disturbance in a structure having unique structural characteristics is minimized. Actuators are operated in response to complex input signals to produce counteractive forces in the structure. Sensors responsive to the vibrational disturbance and the counteractive forces produce outputs indicative thereof. A processor having an electrical characteristic related to the structural characteristic produces complex outputs for each actuator in response to the sensor inputs. The complex outputs are adjusted by the processor to result in a convergence of the structural response to the minimum vibration in response to the disturbance and the actuator inputs.

Abstract: An undoped surface layer over and lattice matched to the n-channel layer between the gate contact and the spaced apart source and drain n+ regions in power FETs made of group III-V compounds minimizes surface effects that preclude such devices from operating efficiently at high voltages, and improves reliability. The undoped surface layer may be grown on the n-channel layer before the layer forming the n+ regions, or where the n+ regions can be formed in the undoped surface layer. The invention is especially suitable for GaAs MESFETs and HEMTs.

Abstract: Both a co-fired ceramic package for a power circuit is disclosed as well as a method of manufacture thereof. The package includes a base which is formed from a plurality of pyrolizable ceramic films, each of which includes a heat-conductive and electrically insulative ceramic material such as aluminum nitride, silicon carbide or beryllium oxide embedded within a binder. In the method of the invention, two or three ceramic films are metalized with a pattern of conductive material on their top surfaces. The resulting metalized films are then stacked over a plurality of unmetalized ceramic films, and the resulting aggregate stack is laminated together by the application of heat and pressure. Electrical components are then soldered onto the top surface of the base, and a cover is sealingly connected around the resulting hybrid circuit. The metalization step advantageously forms terminals around the cover which allow access to the heat generating power circuit without the need for glass post seals.

Abstract: High resolution scintillation counters comprise a flat-faced photomultiplier tube 10 optically coupled to a long scintillator rod 30 having reduced internal light reflectance 45 and a medium 55 between the photomultiplier tube and the scintillator, said medium having both an index of refraction less than that of the scintillator and the capacity to attenuate light traveling from the scintillator to the photomultiplier on the basis of the light's point of origin within the scintillator. In preferred embodiments, the medium comprises air. The scintillation counters disclosed are useful in the detection of electromagnetic radiation, especially gamma rays.

Abstract: A constant false alarm rate (CFAR) circuit uses three windows for calculating mean level thresholds. In addition to a lead window and a lag window each separated from a cell of interest by a predetermined number of cells, a straddle window is used which includes the cell of interest. Each of the lead, lag and straddle windows are subjected to editing to remove three adjacent cells including the cell with the highest power level. The remaining cells are used to calculate a mean level threshold for each of the three windows. The largest of the three mean level thresholds is used, unless it is derived from the straddle window and it is significantly larger than the largest of the mean level thresholds derived from the lead and lag windows. In addition, use of the mean level threshold derived from the straddle window may be excluded for range cells associated with one or more range and azimuth.

Abstract: A cascode radio frequency amplifier in which a control amplifier stage is provided and any number of clone amplifier stages are connected in series (cascode) with the control amplifier. The cascode amplifiers provide equal voltage and power since each of the clone stages provides unity gain. The device can operate from low frequencies to high frequencies.

Abstract: A high definition television acoustic charge transport filter bank significantly lowers the amount of digital processing needed in a high definition television. The filter bank effects frequency shifting by undersampling input waveforms to create aliasing, and by sampling output waveforms to shift received signals up in frequency. The filter bank is highly accurate and inexpensive because of the simple acoustic charge transport filter structure, high charge transport efficiency, linear phase and sample data operation.

Abstract: An improved heliostat device for an electrooptical system in which a mirror is gimbaled in two axes for line-of-sight direction and stabilization. A half angle drive system is connected to the mirror for controlling azimuth rotation of the mirror relative to the stable body from which the mirror is mounted. The half angle drive system comprises a N-2N-speed synchro transmitter-receiver pair, with the N-speed synchro control transmitter mounted on the stable body axis, and the 2N-speed control receiver mounted on the mirror axis. This synchro transmitter-receiver pair is operable with a null error signal controlling mirror drive such that the angular rotation of the mirror is one-half that of the angular rotation of the stable body.

Abstract: A high performance, high current, miniaturized low voltage power supply is disclosed which employs a thick copper-ceramic film primary board, a direct bonded copper secondary, flexible printed circuit power inductors, the power supply has high power leadless chip carriers, hybrid rectifier packages and various electrical circuits including application specific integrated circuits for control, a turn on protection and current sharing.

Abstract: A frequency selective limiting device is described incorporating a pair of generally planar ferrite members and a plurality of signal-carrying conductors positioned between the ferrite members. The plurality of signal-carrying conductors are located on a single YIG substrate. A D.C. bias field may be generated by a common magnetic source positioned on the surface of the substrate opposite the plurality of signal-carrying conductors.

Abstract: An oscillator circuit is coupled to receive first and second reference signals and includes a voltage-controlled oscillator for generating an oscillating signal. A difference frequency calculation circuit is coupled to the voltage-controlled oscillator to produce a count signal corresponding to a difference in frequency between the oscillating signal and the first reference signal. A feedback circuit is coupled to the difference frequency calculation circuit and coupled to receive the second reference signal which corresponds to a predetermined frequency for the oscillating signal. The feedback circuit provides a control signal as an input to the voltage-controlled oscillator to control the frequency of the oscillating signal.

Abstract: A pulsed laser arc welding method and apparatus whereby a pulsed input laser beam is generated by a laser pulse generator to cause an ionized plasma cloud to be generated at a worksite. A power supply supplies energy to an arc welding device, which is stored in a capacitor therein. This energy is drawn out of the storage capacitor once the ionized plasma cloud is sufficiently conductive. Control circuitry is provided to control the pulse repetition frequency of the laser pulse generator and to control the energy dissipation from the storage capacitor in the arc welding device.

Abstract: A frequency division multiplex guardband communication system is provided which increases the communication capability of conventional FDM systems with negligible effect on overall system performance. The additional capacity is achieved through the use of guardbands which lie between the information bands of the FDM. To avoid interfering with recovery of the FDM information, the amount of new signal energy added to the individual guardbands is well below the guardband noise level.

Abstract: A digital-to-analog converter for an acoustic charge transport (ACT) device that permits an ACT device to directly accept digital inputs. The digital-to-analog converter includes a plurality of digital-to-analog converter circuits that convert respective groups of digital information applied to the ACT device to corresponding analog voltages. The corresponding analog voltages are applied to respective input contacts that are isolated by charge barriers formed in a channel region of the ACT device. Each of the input contacts generates a charge packet having a charge magnitude corresponding to a numerical value of an input group of the applied digital information. The charge packets generated by each of the input contacts coalesces into a collective charge packet which then travels through the ACT device.

Abstract: A phase detector receives two input digital signals representing Cartesian coordinates of a vector and outputs a digital signal indicative of the phase angle of the vector. The input digital signals are logarithms of the square of, for example, in-phase and quadrature components of a radar signal and are subtracted in the phase detector to produce a difference signal having a magnitude and a polarity. The polarities of the difference signal and the two information signals are used to determine the octant of the phase angle by addressing a read only memory. The magnitude of the difference signal is used as an address of a read only memory storing digital values corresponding to angles within an octant. The octant output by the first read only memory and the angle output by the second read only memory together indicate the phase angle of the vector.