Abstract: In a DH-PHEMT the channel layer comprises InGaAs, the donor layers comprise In.sub.y Ga.sub.1-y P(0.15.ltoreq.y.ltoreq.0.85), and each of the spacer layers comprises an In.sub.0.5-q (Al.sub.x Ga.sub.1-x).sub.0.5+q P outer spacer layer (0.2.ltoreq.x) and an Al.sub.r Ga.sub.1-r As (0.ltoreq.r.ltoreq.0.3) inner spacer layer. In another embodiment, a similar InAlGaP layer forms a Schottky barrier gate contact with a barrier height of at least 1.0 eV and hence low leakage current. The devices exhibit the capability for both low noise and high power operation at low supply voltages.

Abstract: Bit error rate in holographic storage/reconstruction is reduced by 2-dimensionally dispersing symbols constituting codewords so that no two codeword-common symbols occupy a single row or column on the SLM display.

Abstract: A method and apparatus are disclosed that mitigate the induction of baseband interference that can from time-division radios (e.g., radios that radiate an RF signal with a time-varying power envelope). A radio comprising an embodiment of the present invention radiates, in transmit mode, an information-bearing signal. In some or all idle modes, the radio radiates at least one energy-reducing pulse, but in an idle-mode channel. These energy-reducing pulses reduce the energy in the fundamental frequency component of the average RF power envelope of the radio and also reduce the energy in the harmonics of the fundamental frequency.

Abstract: A method and apparatus for performing joint stereo coding of multi-channel audio signals using intensity stereo coding techniques. In particular, predictive filtering techniques are applied to the spectral coefficient data, thereby preserving the time structure of the output signal of each channel, while maintaining the benefit of the high bit rate savings offered by intensity stereo coding. In one illustrative embodiment of the invention, the input signal is decomposed into spectral coefficients by a high-resolution filterbank/transform; the time-dependent masking threshold of the signal is estimated using a perceptual model; a filter performing linear prediction in frequency is applied at the filterbank outputs for each channel; intensity stereo coding techniques are applied for coding both residual signals into one carrier signal; the spectral values of the carrier signal are quantized and coded according to the precision corresponding to the masking threshold estimate; and all relevant information (i.e.

Abstract: The invention uses a connection having a predetermined priority, switched through the existing call processing switch fabric, to connect between customer premise equipment (CPE). The connection is implemented such that the connection is disconnected if an incoming call to one of the CPEs or an outgoing request for service from one of the CPEs is made that has a priority higher than the predetermined priority. If the connection is disconnected due to a request for higher priority service, the system of the invention can automatically reestablish the connection after the higher priority service call has ended.

Abstract: An improved modulator and methods for making the modulator are disclosed. A membrane, preferably circular in shape, is formed over a region of a substrate in such a way that a gap results between the membrane and substrate forming a modulator cavity. The membrane forms a continuous surface over the cavity. In particular, the membrane is not supported by discrete support arms, but rather extends beyond the modulator cavity. Preferably, holes are formed in the membrane to aid in damping its motion and to allow access to underlying layers during modulator formation. According to the method, the modulator is formed by forming a means for creating a gap between the substrate and the membrane, forming a membrane, forming a lateral conduit to aid in removing the means for creating the gap and, finally, by removing the means for creating the gap.

Abstract: A channel assignment system allocates channels to various cells by the optimal partitioning of the available radio frequencies into non-overlapping sets, the optimal grouping of co-user cells, and the best allocation of the former to the latter. Maximization of traffic handling capacity is, for one embodiment, expressed as the maximization of a bottleneck capacity ratio, known as the capacity factor. The capacity ratio for a cell is defined as the ratio of the number of radio frequencies allocated to the cell over the number of radio frequencies needed to meet blocking probability requirements. Given a channel allocation, the latter is fixed once the traffic loads and desired blocking are specified. The solution to attain an optimal non-regular channel assignment is decomposed into two mathematical programs designated a Master Program and a Subprogram. These are solved iteratively with assistance from a channel set augmentation technique implemented between solutions of the Master and Subprogram.

Abstract: A digital phase detector which generates low jitter when the phase-locked-loop is in lock. A delay line, combined with an UP/DOWN phase detector causes substantial overlap in the UP and DOWN signals from the detector. When the PLL is in lock, the overlapping signals substantially cancel each other out, minimizing the variations in the output frequency. Two approaches are disclosed: one delaying the UP signal sufficiently to overlap the DOWN signal, the other using a delay and an exclusive OR gate to generate the DOWN signal.

Abstract: Improved radio receiver designs are disclosed that can be used in the operational environment of wireless communications. The radio receiver includes a signal input terminal, a variable-current RF signal amplifier, a demodulator, and a controller. The variable-current RF signal amplifier has an input terminal for accepting RF input signals, an output terminal for generating an amplified version of the RF input signals, and a current control terminal for controlling the current consumption of the RF signal amplifier. The signal input terminal is coupled to the input terminal of the variable-current RF signal amplifier, the output terminal of the variable-current RF signal amplifier is coupled to the demodulator, and the current control terminal is coupled to the controller. The controller is also coupled to the demodulator. A received signal, including any noise and/or interference, is coupled to the signal input terminal.

Abstract: A blind equalization technique uses both the "constant modulus algorithm" (CMA) and the "multimodulus algorithm" (MMA) during blind start-up. This approach provides the basis for a "transition algorithm." One example of a transition algorithm is the CMA-MMA transition algorithm in which an adaptive filter simply switches from CMA to MMA. Other examples are variations of the CMA-MMA transition algorithm and are illustrated by the "Constant Rotation CMA-MMA" transition algorithm and the "Dynamic Rotation CMA-MMA" transition algorithm.

Abstract: A method of depositing aluminum or other metals so that vias are more completely filled is disclosed. The wafer or substrate is preheated to a temperature of approximately 200.degree. C. Then the wafer is placed in an ambient of approximately 350.degree. C. while metal deposition commences. The resulting metal layer has a gradually increasing grain size and exhibits improved via filling. Also disclosed is a method and apparatus (involving cooling of support structures) for deposition of an anti-reflective coating to prevent rainbowing or spiking of the coating into the underlying metal.

Abstract: The present invention is directed to a method of resolving protocol addresses using new protocols. Gateways that map ATMARP packets to NHRP packets are placed in the network to make translations between the two protocols. Therefore the installed base of networks can be maintained, with added functionality. Techniques for handling those areas where the two protocols do not match directly such as sub-address fields, purge packets and holding time expiration are also disclosed.

Abstract: A surface analysis system can contactlessly, automatically, and rapidly detect, classify, and evaluate a surface of an object, particularly, an optical fiber end face, for discontinuities to derive a single pass/fail conclusion regarding the surface. The surface analysis system has a scope for capturing an image of the end face. A computer is connected to the scope. A machine vision system is associated with the computer for receiving the image. A surface analysis program is associated with the computer for driving the machine vision system. The program searches for any discontinuities in the image by analyzing each pixel and a corresponding pixel structure of pixels to determine whether a discontinuity resides at each pixel. Discontinuities are classified as one of the following: binary thresholds, local gradients, and directional gradients. The pixel structure includes a plurality of pixels that were previously analyzed.

Abstract: In accordance with the invention, a field emission device is made by disposing emitter material on an insulating substrate, applying masking particles to the emitter material, applying an insulating film and a gate conductor film over the masking particles and emitter material and removing the particles to reveal a random distribution of apertures to the emitter material. The result is a novel and economical field emission device having numerous randomly distributed emission apertures which can be used to make low cost flat panel displays.

Abstract: A method for quantitatively and objectively measuring the usability of a system. The method provides quantitative measures for usability satisfaction, usability performance, and usability performance indicators. Usability satisfaction is measured by acquiring data from a system user population with respect to a set of critical factors that are identified for the system. Usability performance is measured by acquiring data for quantifying the statistical significance of the difference in the mean time for an Expert population to perform a task on a particular number of trials and the estimated mean time for a Novice population to perform the task on the same number of trials. The estimated mean time is calculated according to the Power Law of Practice.

Abstract: The present invention monitors the RF drive circuitry of a linear laser transmitter. In one preferred embodiment of the present invention, a filtered RF signal from the monitor diode is amplified and then input to a peak detector. The output of the peak detector is then fed to the input of a threshold detector, wherein the threshold detector determines whether the output of the peak detector is above a predetermined threshold. If the output of the peak detector falls below the predetermined threshold an alarm is generated at the status monitoring ports of the laser transmitter.

Abstract: To provide a monolithic ATM transport the synchronous to asynchronous converter (SAC) of the invention converts the synchronous narrowband signals to composite cell ATM format. These cells can be combined with ATM video and data signals and can be delivered as an ensemble of ATM cells over either a standard SONET transport format or analog network to the customer premise. To convert the synchronous signals, the SAC provides format conversion needed to provide voice and other narrowband signals over ATM. The SAC also functions to agilely move between cell sizes such that the 48 bytes of the cell payload can be mapped to carry anywhere between the single and 48 connections. Thus, the SAC adjusts the cell configuration to balance performance and bandwidth use in a real-time manner.

Abstract: An apparatus and method for centralized processing of PIP images from a plurality of digital video sources includes a centralized processing device having a plurality of service drivers for outputting digital video data representing full screen images, and samplers for selectively sampling the data from the service drivers to form reduced screen images. A PIP bus channels the sampled data for access by various users. The sample data is selectively stored in buffers and is output to a display device when triggered by input/output triggers. The triggered output data representing reduced screen images is then combined by a video switch to form picture-in-picture images.

Abstract: A timing recovery process for digital receivers employing decision-feedback equalization (DFE) or delayed decision-feedback sequence estimation (DDFSE) can be executed prior to equalization, minimizes training complexity, and provides fast equalizer start-up for transmissions of short packets. The optimum symbol timing and burst timing is determined by (i) calculating a signal-to-intersymbol interference-plus-noise ratio (SINR) index by estimating the channel impulse response and the noise power, and (ii) varying the symbol timing and the burst timing to maximize the calculated SINR index. The timing recovery process particularly improves performance of a digital receiver utilizing (a) decision-feedback equalizer structures in which the delay spread is large compared to the span of the feedforward filter, and (b) equalizer structures based on delayed decision-feedback sequence estimation in which the delay spread is large compared to the memory of the Viterbi sequence estimator section.