Abstract: A dual polarized printed circuit antenna operating in dual frequency bands. A first array of radiating elements radiates at a first frequency, and a second array of radiating elements radiates at a second, different frequency. Separate power divider arrays are provided for each array of radiating elements, and the overall structure is provided in a stacked configuration.

Abstract: The steady state condition of a subject product is projected using transient data developed through actual or simulated tests or operations. The transient data represent the monotonic or cyclic property states of the product while subjected to environmental or operational conditions. A first and second property state value corresponding to the transient data for selected times within the test period are identified. A first and second rate-of-change value corresponding to the change in the property states at the selected times are then computed. A time constant value is next computed by applying the time interval and the first and the second rate-of-change values to a time constant function. A projected steady state condition value is next computed by applying the second rate-of-change value, the second state value and the time constant value to a projected steady state conditions function. The projected steady state condition value is compared with a previously computed projected steady state condition value.

Abstract: Improved automatic gain control for an amplifier is obtained by controlling the size of a null zone in a drive signal for the amplifier. The size of the null zone is controlled by estimating strength of an interference signal, and dynamically varying the size of the null zone based on the estimated strength of the interference signal. As a result, the amplifier rarely saturates, regardless of signal strength. The invention is useful to reduce the harmful effects of jamming or interference.

Abstract: A common pressure vessel type Ni--H.sub.2 storage battery having an outer pressure vessel that contains a stack of compartments. Each of the compartments including at least one battery cell, a heat transfer member, and a cell spacer for maintaining a relatively constant distance between adjacent compartments. The heat transfer members include a fin portion, which is in thermal contact with the battery cell, and a flange portion which extends longitudinally from the fin portion and is in tight thermal contact with the inner wall of the pressure vessel. The heat transfer member serves to transfer heat generated from a battery cell radially outward to the pressure vessel, which is capable of dissipating the heat into the surrounding atmosphere.

Abstract: An intercell connector for electrically interconnecting a plurality of battery cells, each of the battery cells including a plurality of spaced apart positive and negative electrode plates encased in a plastic casing. The intercell connector includes first and second buss bars disposed in spaced apart relation to each other and each including a base portion and an electrode connecting portion extending from the base portion, the base portions of the first and second buss bars respectively including first and second electrode terminals aligned with each other; and an insulator for insulating the first and second buss bars from each other. The connector is disposed in the casing of each of the cells so as to extend transversely to the electrode plates with the casing being bonded to a portion of the insulator such that only the electrode terminals are exposed outside the casing.

Abstract: A compound time-multiplexed video transmission processing system transmitting and receiving a signal corresponding to luminance signal for driving a video display includes a transmit processor for processing a received luminance signal to produce a time-multiplexed mixed field signal based on a high frequency signal corresponding to a high frequency portion of the input luminance signal received during a previous field and a half bandwidth signal received during a current field, and a receive processor for processing the mixed field signal to produce an output luminance signal based on the high frequency portion and the half bandwidth signal. The transmit processor includes circuitry for storing the high frequency portion of the input luminance signal from the previous field. The system produces an artifact in the mixed field signal, which is evenly distributed in the output luminance signal in a predetermined processing sequence. A method for processing luminance signals is also disclosed.

Abstract: A low-bit-rate, low-cost, all-digital preambleless demodulator for maritime and mobile data communications operates under severe high noise conditions, fast Doppler frequency shifts, large frequency offsets, and multipath fading. Sophisticated algorithms, including an FFT-based burst acquisition system, a cycle-slip resistant carrier phase tracker, an innovative Doppler tracker, and a fast acquisition symbol synchronizer, provide reliable burst reception. The compact DSP-based demodulator includes an input buffer receiving a complex sampled baseband input signal and providing a baseband output to a coarse frequency estimator fast Fourier transform (FFT) or discrete Fourier transform (DFT) module which produces a first estimation of the carrier frequency. A fine frequency estimator FFT or DFT module receives the first estimation and provides a second estimation of the carrier frequency. An extra coarse frequency estimator FFT or DFT module may be provided between the buffer and the coarse frequency estimator.

Abstract: The present invention is directed to reducing the number of components required to minimize intermodulation distortion within the wide transmission frequency band used by a satellite communications repeater system. In particular, at least two TM.sub.010 mode cavity is cascaded to a plurality of TE.sub.113 mode cavities to form a narrow band-pass, wide band-stop filter for receiving and outputting channel signals to the multiplexer manifold of a satellite repeater. The filter thus constructed realizes the narrow band-pass response required in microwave communications, while eliminating the spurious resonance frequencies normally eliminated by additional filter components. In this manner, the size and weight considerations of the satellite system are improved without loss in performance.

Abstract: A low-rate encoding/digital speech interpolation (LRE/DSI) system architecture is organized to eliminate the LRE mistracking problem normally associated with DSI-induced speech clipping, to reduce the number of LRE codes required and to provide a mechanism for gradually introducing overload.

Abstract: A "modified rearrangeable" switch matrix combines both .beta. switching elements and crossbar switch matrices in a single switch configuration, with .beta. switching elements used at the input and output and at least one crossbar switch matrix in the middle to receive its inputs from .beta. switching elements and provide its outputs to .beta. switching elements.

Abstract: An apparatus for obtaining carrier synchronization acquisition in a digital burst mode communication system is provided. An accurate estimate of the carrier phase of the unmodulated preamble, .theta., is obtained by determining which of 256 intervals X.sub.o.sup.2 +X.sub.e.sup.2 fall into, and by evaluating which of 256 intervals Y.sub.o.sup.2 +Y.sub.e.sup.2 fall into. A quantized value is assigned to the generated output code for both X and Y inputs. The square root and arc tangent are evaluated to determine the value .theta..

Abstract: A residual signal quantization technique used in the adaptive predictive coding of speech signals is based in the frequency domain. In predictive coders, a residual signal that results after redundancies are removed from the input signal using linear prediction techniques is quantized. The technique invented involves a transformation of the residual signal to the frequency domain and a quantization of the frequency domain coefficients. Further, the number of bits used to quantize each frequency coefficient is determined by an estimate of the power of the input signal at that frequency. Once the number of bits to be used for quantization is determined, the quantization noise power spectrum is shaped, and can be selectively shaped so as to form a desired reconstruction noise power distribution.

Abstract: A planar doped valley field effect transistor (PDVFET), which positions more than one two-dimensional electron gas (2DEG) layer within a homo-structure (GaAs), in order to improve the FET's power output. The FET includes two 2DEG donor planes with an undoped GaAs layer therebetween, and a n-doped GaAs layer on the other side of each donor plane. The FET also includes a 2DEG acceptor plane below the n-doped GaAs layer, which is furthest from the contacts. This 2DEG plane combination forms a deep and wide valley in the FET's conduction band, which improves the FET's power output.

Abstract: Electrical devices are characterized by optically triggering an electrical signal onto the device and then optically sampling the electrical signal waveform on the device.

Abstract: A carrier frequency lock detection circuit receives a baseband signal from a tuning control loop of a receiver. The baseband signal is sent to a comb-filter network which has a plurality of bandpass filters, each receiving a specific sideband frequency. The output power of each filter of the comb-filter network is added up by an adder, filtered by a multiple low-pass filter to reject noise components, and finally converted to a voltage. The thus converted voltage is compared to a preset threshold voltage in order to determine whether the carrier signal has passed through one of the filters of the comb-filter network intended for a sideband, thus indicating that the tuning control loop of the receiver is locked onto a sideband frequency. If such a situation exists, a break-lock indication is sent to the receiver.

Abstract: A compact multi-layer flat antenna structure incorporating a low noise block down-converter on the power divider network layer of the antenna. RF circuit losses are reduced, and the antenna/receiver combination is made more compact, for flush mounting. The antenna/receiver combination finds particular utility in direct broadcast satellite (DBS) applications for single or dual orthogonal polarizations. The connection between the antenna and receiver may be implemented in stripline/coplanar waveguide, or other known technologies such as microstrip, slotline, and finline.

Abstract: A pay television subscriber pays for viewing credits which are transmitted to the subscriber equipment from a central office. Each program is associated with a pulse having a rate corresponding to the charge per unit time for that program, and the viewing credits are debited appropriately.

Abstract: Integration and packaging of monolithic microwave integrated circuits (MMIC) components is facilitated by using a motherboard comprising high resistivity silicon, which having a thermal conductivity three times that of gallium arsenide. Ultra high purity, uncompensated silicon preferably is used. Anisotropic etching of recesses in the motherboard facilitates precise placement of the MMICs in the recesses, enabling use of automated die and wire bonding techniques to reduce required assembly time substantially. Using a silicon motherboard also ultimately enables incorporation of required control circuitry. The silicon motherboard also transmits RF energy well, a useful characteristic particularly in C-band and X-band applications in which microstrip is used, though other transmission media function well at even higher frequencies.

Abstract: An RF power combiner combines the power of several microwave high power FET amplifiers. A plurality of baluns which convert a balanced transmission line to an unbalanced transmission line and have outputs which are 180.degree. out of phase from each other may be connected at the inputs and the outputs of the FETs. This connection allows for very high output power while matching impedances of the input and the output of the power combiner. Additionally, loss in the output circuit can be minimized by connecting equi-phase outputs of the FETs in a parallel/push-pull manner.