Abstract: An optical modulator comprises at least two optically coupled MARS modulators, at least one having positive spectral tilt and at least one having negative spectral tilt. Both tilt and attenuation can be independently controlled by adjusting the air gaps of the constituent modulators. Preferred designs present linear spectral tilt.

Abstract: Interference signal power in a TDMA communication system is determined by taking samples of a received signal. The TDMA system has a plurality of communication frequencies with sequences of frames communicated at each of the communication frequencies. Each of the frames contain a plurality of time slots, where each time slot is associated with a communication channel. The interference signal power is determined by receiving a signal at one of the plurality of communication frequencies. The signal is sampled for at least one frame period. The interference signal power is calculated using the M larger amplitude samples of the signal, where M is the number of samples that are taken during a period of time that corresponds to a length of one time slot.

Abstract: A bipolar fabrication process, illustratively suited for integration into a conventional CMOS process to thereby form a BiCMOS integrated circuits is disclosed. The collector and base are formed through multiple implants and a single masking step to thereby provide a continuous low resistance collector region.

Abstract: A method of extracting an information bearing signal .omega.(n) from a base-band signal in the form of an inverse function with a digital signal processor. The processor includes memory and utilizes a minimum number of instructions stored in the memory. The base-band waveform comprises a plurality of complex-valued samples having respective I and Q components. The method includes the steps of receiving a first sample at an instant n having respective I(n) and Q(n) components and defining an interval for evaluating potential values for the I(n) and Q(n) components. Next, a step of transforming said I(n) and Q(n) components is performed to have respective threshold values residing in the predefined interval. Then, a step of estimating the transformed components with a series of non-inverted polynomial functions is carried out over the predefined interval.

Abstract: A wireless telecommunications system is disclosed that is capable of providing both public wireless service and virtual private network service on existing IS-95 CDMA facilities without changes to the air interface, the hardware design or the protocols for interacting with home location registers. An illustrative embodiment of the present invention comprises: broadcasting from a radio a first SID/NID signal and a FOR.sub.-- NID.sub.

Abstract: A method of training a TTS or other system to assign intonational features, such as intonational phrase boundaries, to input text that overcome the shortcomings of the known methods is described. The method of training involves taking a set of predetermined text (not speech or a signal representative of speech) and having a human annotate it with intonational feature annotations. This results in annotated text. Next, the structure of the set of predetermined text is analyzed to generate information. This information is used, along with the intonational feature annotations, to generate a statistical representation. The statistical representation may then be stored and repeatedly used to generate synthesized speech from new sets of input text without training the TTS system further. The resulting trained system and use thereof are also part of the invention.

Abstract: A security override system for a padlockable structure comprising a hasp portion mounted to the structure and extending through an opening in an outer surface of the structure; a bracket mounted to the outer surface, the bracket having a latching end and being movable between an open position wherein the latching end is outside the opening in the structure and a closed position wherein the latching end extends through the opening; the bracket mating with the hasp portion when in a closed position for forming a padlock receiving portion; the latching end engaging a retention plate slideably moveably mounted within the structure proximate the opening, the retention plate slideably movable between an extended position wherein the retention plate engages the latching end when the bracket is in the closed position and a retracted position wherein the retention plate does not engage the latching end when the bracket is in the closed position; a security screw extending through an opening in the outer door and conne

Abstract: A modular power supply and a method of operating the same to accept either AC or DC input power. In one embodiment, the modular power supply includes an input module that accepts input power and employs at least one main power switch and a step-up transformer to provide intermediate power at an enhanced voltage at an output thereof. The modular power supply also includes a power transfer conductor coupled to the output. The modular power supply further includes an output module, having an input coupled to the conductor, that accepts the intermediate power and employs a step-down transformer and an output rectifier to provide DC output power at a voltage that is less than the enhanced voltage. The modular power supply still further includes a diode, coupled to the input and output modules, that prevents the step-up and step-down transformers from saturating.

Abstract: An optical circulator is disclosed that utilizes a polarization rotator comprising a polarization changer (e.g., a properly-oriented half-wave plate) in combination with a pair of latched garnet Faraday rotators. The latched garnet rotators are positioned next to each other and oriented so that one latched garnet rotator provides clockwise rotation and the other provides counterclockwise rotation. The use of latched garnet with a single half wave plate results in an arrangement that is reduced in overall size and does not require epoxy to interconnection the various piece parts.

Abstract: Apparatus for processing a silicon workpiece uses reflected UV light to measure and control the workpiece temperature. A linearly polarized beam including UV light is directed onto a silicon surface to produce a reflected beam. The reflected beam is cross-polarized to null out much of the light, and the resulting residual reflectivity spectrum is determined. The temperature is determined from the characteristics of this spectrum. A workpiece heating station uses this measuring technique to accurately control the temperature of a silicon workpiece and temperature-dependent processing over a wide range of processing temperatures, including temperatures below 500.degree. C.

Abstract: An electronic device is formed by depositing a thin film of high dielectric constant material on a silicon substrate, exposing the structure to plasma, and then forming the top electrode. The plasma substantially reduces the density of charge traps at the dielectric/silicon interface. Advantageously, the dielectric film is passivated with a nitrogen-containing material before forming the top electrode to prevent interdiffusion between the electrode and the dielectric.

Abstract: A dispersive optical waveguide tap comprises a blazed refractive index grating in the core of the waveguide, coupling means, focusing means and utilization means. The grating is selected such that guided mode light of predetermined wavelength will, in the absence of the coupling means, be directed into one or more cladding modes of the waveguide. The presence of the coupling means, in optical co-operation with the waveguide, changes the guiding conditions such that the cladding modes are substantially eliminated from a portion of the waveguide that includes the cladding, whereby the grating directs the guided mode light into one or more radiation modes. The blaze angle typically is .ltoreq.15.degree.. The focusing means serve to bring the radiation mode light substantially to a focus in at least one dimension, the focal point (or line) depending on the wavelength of the light.

Abstract: A method of testing field programmable gate arrays (FPGAs) includes the step of configuring programmable logic blocks of the FPGAs for completing a built-in self-test. This is followed by the steps of initiating the built-in self-test, generating test patterns with the programmable logic blocks and analyzing a resulting response to produce a pass/fail indication with the programmable logic blocks. More specifically, the configuring step includes establishing a first group of programmable logic blocks as test pattern generators and output response analyzers and a second group of programmable logic blocks as blocks under test. The blocks under test are then repeatedly recongifured in order to completely test each block under test in all possible modes of operation. The programming of the first and second groups of programmable logic blocks is then reversed and the testing of each new block under test is then completed.

Abstract: A synchronous rectifier, a method of operating the same and a power converter incorporating the synchronous rectifier or the method. In one embodiment, the synchronous rectifier includes: (1) a plurality of parallel-coupled active rectifier circuits, each of the plurality of active rectifier circuits having first and second rectifier switches coupled to corresponding first and second voltage limiting switches and (2) a controller, coupled to the plurality of active rectifier circuits, that senses a through-current of the rectifier and employs the voltage limiting switches to disable corresponding ones of the plurality of active rectifier circuits as the through-current decreases to enhance an operating efficiency of the synchronous rectifier.

Abstract: A security override system for a locked box comprising a first hasp portion mounted within a box and extending through an outer door of the box; a second hasp portion connected to a bracket; the bracket slideably mounted within the box such that the second hasp portion extends through an opening in the outer door; the bracket being movable between a closed position wherein the second hasp portion mates with the first hasp portion to form a padlock receiving section and an open position wherein the second hasp portion does not mate with the first hasp portion; and wherein the outer door can be opened by moving the bracket into the open position and removing a locked padlock inserted in the padlock receiving section without first unlocking the padlock.

Abstract: A free-space N by M, where N and M>1, optical signal switch (OXC) requires only transmitter beam steering for controlling to which receiver an optical signal from a transmitter is directed. In a preferred embodiment the transmitters handle single mode optical signals and the receivers handle multimode optical signals. The OXC may optionally include a fixed optical unit implemented using either a single fixed shared lens or a plurality of M optical elements for further directing each of the M optical signals to their respective receivers.

Abstract: An integrated circuit includes at least one non-volatile memory element having first and second non-volatile transistors connected in series between first and second data lines. A junction between the first and second non-volatile transistors forms an output node. The non-volatile memory element further includes an access transistor connected between a reference voltage line and the junction between the first and second non-volatile transistors. In a programmable logic application, for example a field programmable gate array, the non-volatile memory element controls the state of a switching element, which selectively connects logic elements in the programmable logic application. Based on the voltages applied to the non-volatile memory element, the non-volatile memory element is selectively erased, programmed, operated, monitored and powered-up.

Abstract: A split-boost converter having a main inductor, first and second main switches and floating and fixed outputs and a method of operating the same. In one embodiment, the converter includes an auxiliary diode coupled between the main inductor and a first rail of the floating output, and an auxiliary switch coupled to a node between the main inductor and the auxiliary diode and a second rail of the floating output. The converter is operable in a first mode, when an input voltage of the converter at least equals an output voltage of the converter, in which the auxiliary switch remains open and the first and second main switches are modulated to operate the converter. The converter is further operable in a second mode, when an input voltage of the converter is less than an output voltage of the converter, in which the first and second main switches remain closed and the auxiliary switch is modulated to operate the converter.

Abstract: We have recognized that there is a strong need to control and maintain the secrecy of the intelligence that may be used by computers to communicate with another, for example, by encrypting the messages that they exchange with one another. Thus, the encryption keys used to encrypt such messages need to be managed in a highly secure manner. Accordingly, we provide an encryption module, which, in accord with an aspect of the invention, generates a unique device encryption key (S.sub.local), a cryptographic key formed from a unique identification key (S.sub.id) and an associated public key (KP.sub.id), and at least one program encryption key, in which the public key is generated as a function of the unique identification key. The module then encrypts the unique identification key and program encryption key using said device encryption key and stores the encrypted result in memory internal to security module, thereby securing the keys against misappropriation.

Abstract: The invention provides protocols for managing transactions operating on replicated data items at multiple physical sites in a distributed database system. The protocols make use of dynamically changing sets of data items referred to as "virtual sites" and a replication graph or other suitable globally consistent representation of the relationships between the transactions and the virtual sites. Illustrative embodiments of the invention include a static global serializability (SGS) protocol, a commit-oriented protocol (COP) and a multiversion optimistic protocol (MOP). The SGS protocol broadcasts the data access set of a given transaction to all physical sites, and applies the Thomas Write Rule (TWR) to write-write conflicts on secondary copies of data items. The COP protocol defers testing of the replication graph until a transaction is ready to commit, and each transaction is allowed to proceed at its origination site independently of other transactions that are executing at other sites.