Abstract: The present invention provides viewing and monitoring equipment that can remotely operate and control test equipment to monitor optical links of a communication system and to determine whether the optical links are operating properly.

Abstract: Fraud losses in a communication network are substantially reduced by automatically and selectively invoking one or more authentication measures based on a fraud score that indicates the likelihood of fraud for that particular call or previously scored calls. By selectively invoking authentication on only those calls that are suspected or confirmed to be fraudulent, fraud prevention can be achieved in a way that both reduces fraud losses and minimizes disruptions to legitimate subscribers. Using telecommunication fraud as an example, a subscriber is registered in a system by collecting data on that subscriber based on the particular authentication method being used, such as shared knowledge (e.g., passwords), biometric validation (e.g., voice verification), and the like. Once registered, the authentication function for the subscriber's account is activated and subsequent calls are then scored for the likelihood of fraud during the call setup request phase.

Abstract: A signature verification method involves segmenting a smoothed and normalized signature and, for each segment, evaluating at least one local feature, thereby to obtain a feature-value vector. The method further includes computing the likelihood that the segments having the observed sequence of feature values were generated by a particular hidden Markov model, such model comprising a sequence of states having duration probabilities and feature-value histograms. In one aspect, the invention involves explicit state-duration modeling to account for duration in the respective states underlying the unknown signature. In another aspect, the invention involves computing a measure of signature complexity, and setting the number of states of the hidden Markov model according to such complexity measure.

Abstract: Signal points from a PCM-derived constellation are selected for transmission via a modulation technique which employs different levels of redundancy coding--including the possibility of no redundancy coding--for respective different sub-constellations of the overall PCM-derived constellation. The coding that is employed for at least one of the sub-constellations is carried out independently from any coding that is employed for any of the other sub-constellations. In preferred embodiments, the sub-constellations are non-overlapping portions of the overall PCM-derived constellation, the redundancy codes are trellis codes, and the trellis codes employed in conjunction with sub-constellations having increasingly smaller minimum distance between signal points provide respectively increasing amounts of decibel gain in that minimum distance in order to compensate for that increasingly smaller minimum distance.

Abstract: A type annotation technique such that expressions are assigned and annotated with types in such a way that types can be efficiently maintained during inference without new syntactic restrictions being placed on the expressions or underlying logic within the verification system. More particularly, in accordance with the technique, expressions, i.e. terms, are annotated using a particular labeling scheme such that, during verification, if an expression is annotated the verification may proceed without any additional type inference or type checking with regard to that expression.

Abstract: We have determined that unlike the most multimode silica fiber, multimode polymer fiber often exhibits a delay characteristic that has a broad low dispersion region where propagation delay of spatially restricted optical pulses remains relatively constant. This low dispersion region is centered around the center axis of the fiber core as a function of launch position. By directing a transmitted optical pulse to this region, we have determined that optical pulse dispersion can be significantly reduced without the need for using the prior art technique of using a single mode fiber spliced in series with the multimode fiber to reduce dispersion. A polymer fiber based optical transmission system using this arrangement exhibits relaxed alignment tolerances between the optical source and polymer fiber, while reducing dispersion and increasing bandwidth-length product.

Abstract: A method and apparatus for detecting silent faults in feeding diodes of redundant DC power supplies. The voltages on both sides of the feeding diodes are measured. Arrangements are then made to ensure that if corresponding feeding diodes are both operative, that current flows through a particular one of these diodes. The measurements of voltage under the various conditions will reveal any open or shorted feeding diodes. The voltage across a diode can be altered by heating the diode through the process of heating a power resistor that is in thermal contact with that diode. Alternatively, a controllable rectifier of a power source can be controlled to reduce the voltage of that power source, and thereby drive current through the diode connected to the other power source. Advantageously, this arrangement allows silent faults in these diodes to be detected without substantial risk of causing the failure in the powered system.

Abstract: The present invention relates to an apparatus and method for depositing a film on a wafer. A reactor for depositing a film on a surface of a wafer comprises a processing chamber having an electrode, a ceramic wafer support supporting the wafer and separated from the electrode by a distance of between 230 and 240 millimeters, a gas inlet supplying gas reactants, and a radio frequency inlet supplying radio frequency energy. The reactor further comprises a heating chamber having at least one heat source which heats the wafer. A method for depositing a film on a surface of a semiconductor wafer comprises providing a processing chamber having a ceramic wafer support supporting the wafer and an electrode, separating the electrode from the ceramic wafer support by a distance of between 230 and 240 millimeters, supplying radio frequency energy into the processing chamber, supplying gas reactants into the processing chamber, and heating the wafer.

Abstract: An improved waveguide optical amplifier having an optically transparent first cladding layer, an optically transparent film doped with an optically active material, disposed over the first cladding layer, at least one undoped optically transparent film disposed over the doped film and coating etched walls of the doped film, and an optically transparent second cladding layer disposed over the undoped film. At least a portion of the undoped film disposed immediately adjacent the doped film has an index of refraction which is closer to the index of refraction of the doped film, than to the index of refraction of the second cladding layer and preferably equal thereto. The undoped film covers surface imperfections in the etched walls of the doped film, effectively moving them from the doped film/undoped film interface to the undoped film/cladding layer interface thereby reducing scattering of the high-intensity mode field.

Abstract: An integrated circuit which includes a successive approximation analog-to-digital converter. The successive approximation analog-to-digital converter employs oppositely coupled comparators and logic circuitry to generate a signal upon a bit determination, with the signal latching the determined bit, resetting the comparators for the subsequent bit determination, and if additional bit(s) are to be determined, commencing the subsequent bit determination. The converter may be configured as a single ended, differential or complimentary circuit.

Abstract: An electrical connector assembly has a terminal housing, and a number of electrically conductive connector assembly terminals supported by the housing. The connector assembly terminals have mid-sections that protrude from the housing for contacting terminals of a mating connector, and outside connection ends for making electrical connections with outside circuits. Free ends of the connector assembly terminals next to the terminal mid-sections and opposite the outside connection ends, are positioned inside the terminal housing. An electrical circuit component is mounted inside the terminal housing. The circuit component is connected to the free ends of the assembly terminals, so that the mating connector becomes electrically connected to the circuit component through paths between the mid-sections and the free ends of the assembly terminals, in proximity to the circuit component.

Abstract: The invention provides techniques for implementing secure transactions using an instrument referred to as "executable digital cash." In an illustrative embodiment, a first user generates a piece of digital cash representing an offer made by that user. The piece of digital cash includes a digital certificate authorizing the first user to make specified transfers, and an offer program characterizing the offer. The piece of digital cash is broadcast or otherwise transmitted to one or more additional users, utilizing a mobile agent or other suitable mechanism, such that a given one of these users can evaluate the offer using the offer program. For example, a second user could execute the offer program with a specific bid as an input to determine what that user would receive upon acceptance of his bid.

Abstract: The present invention is a fast fading packet diversity transmission method and system for reducing the effects of multipath fading on slow fading channels. One embodiment of the present invention includes a modulator for modulating information packets and a plurality of M multipliers for transmitting the modulated information packets from M antennas with up to M sets of M fixed phase offsets. Another embodiment of the present invention transmits a first group of information packets from M antennas with up to M sets of M fixed phase offsets and a second group of information packets with M slow time varying phase offsets.

Abstract: The base station system includes a cancellation processor connected to a plurality of conventional signal processors. Under the control of a controller, the signal processors acquire user signals in signals received by the base station antennas. The controller controls the cancellation processor to perform cancellation operations with respect to the acquired user signals. The cancellation processor includes first-nth filter stages. Each filter stage operates in the same manner. A filter stage obtains, in parallel, the acquired user signals from signals supplied thereto by estimating symbols in the acquired user signals under the control of the controller. The cancellation processor also includes a cancellation stage associated with each filter stage. Each cancellation stage cancels, in parallel, the obtained user signals output from the associated filter stage from the signals received by the base station antennas.

Abstract: A method and associated circuitry are disclosed for applying the high column voltage needed to erase and program (write) a flash EEPROM memory. Low voltage CMOS transistors are used for both the read column precharge path and the write/erase data transfer path. This reduces precharge time, increasing the frequency at which the flash memory can be read. This also eliminates the lengthening of precharge time that occurs as the characteristics of high voltage transistors degrade with age. The present invention provides the additional advantage of eliminating the need to use less reliable high voltage transistors in certain off-pitch circuits needed for write and erase functions, thus increasing overall chip reliability.

Abstract: The specification describes a trilevel resist technique for defining metallization patterns by lift-off. The trilevel resist comprises two standard photoresist levels separated by a thin silicon oxide layer with approximate composition SiO.sub.2.

Abstract: A semiconductor device and a method of manufacture therefor. The semiconductor device includes: (1) a substrate having a recess therein, (2) an aluminum-alloy layer located over at least a portion of the substrate and filling at least a portion of the recess and (3) a protective metal layer at least partially diffused in the aluminum-alloy layer, the metal protective layer having a high affinity for oxygen and acting as a sacrificial target for oxygen during a reflow of the aluminum-alloy layer.

Abstract: A system for testing a communication network component connected to a computer controlled apparatus via a data link in which the system automatically simulates telephonic communication with the communication network component. Device communication specification information is sent to a translator device at the computer controlled apparatus which automatically parses the received device communication specification to enable development of test tools for the simulation of telephonic communication between the computer controlled apparatus and the communication network component employed as a system under test. The translator in response to receipt of the device communication specification automatically generates a computer software based model to simulate a network entity, test scripts, and user documentation guide.

Abstract: A control system comprising an electrical circuit that produces distortion where the electrical circuit has a frequency band of operation. Double side band pilot signals are located slightly outside the boundaries of the frequency band of operation so as not to interfere with any signals within the frequency band of operation, but still provide information that the control system uses to substantially cancel the distortion.

Abstract: A passive resistive element is provided in series with a digital variable impedance to produce a highly linear output impedance for a transmission path over a wide range of operating conditions.