Abstract: In an optical fiber transmission system, higher order PMD compensation is realized with a sweeper device at the input to the fiber which converts the polarization of the light beam into a frequency dependent polarization whose rate of change is similar to the rate of change of one of the PSPs of the fiber. The frequency dependent polarization of the light beam is then aligned with one of the frequency-dependent PSPs at the input of the fiber. Furthermore, differential group delay dispersion for a given frequency can be reduced by employing a chromatic dispersion compensator prior to the receiver end of the fiber transmission system. Control of the polarization of the light beam can be facilitated by monitoring PMD in the system, or alternatively, monitoring an effect of PMD in the system, such as bit error rates.

Abstract: A controller and a method for controlling the amount of loss in signal paths of a communication system are disclosed. The method includes sampling the impulse response of an echo cancelling circuit, detecting an abnormal signal condition by comparing the impulse response to a reference, and inserting loss into a first signal path when an abnormal signal condition is detected. One controller configuration for adjusting the amount of loss in the signal paths of a communication system has an adjustable attenuator in the signal path having a control signal input, a memory element which stores a reference, and a comparator having one input connected to the memory of the echo canceler circuit which samples the impulse response, another input connected to the memory which stores the reference, and an output connected to the control signal input of the attenuator.

Abstract: In an optical fiber transmission system, higher order PMD compensation is realized at the output of the transmission fiber. A compensator is placed at the output of the transmission fiber whose PMD vector is equal in magnitude and opposite in direction to the PMD vector at the output of the transmission fiber. The compensator PMD vector sweeps at a rate that matches the frequency sweep rate of the PMD vector at the fiber output. To compensate for second order PMD while avoiding the introduction of higher order PMD effects, a planar sweep is advantageously employed. A polarization pair controller is employed in advance of the compensator to align the PMD vector at the compensator input with the PMD vector at the fiber output so that the two cancel as well as to align the rotational axis of the compensator PMD vector with the rotational axis of the fiber PMD vector. The system may also include a monitoring device to monitor the compensation of fiber PMD, to determine the need for adjustments to the system.

Abstract: The present invention, in one embodiment, provides a method for eliminating agglomerate particles in a polishing slurry. In this particular embodiment, the method is directed to reducing agglomeration of slurry particles within a waste slurry passing through a slurry system drain. The method comprises conveying the waste slurry to the drain, wherein the waste slurry may form an agglomerate having an agglomerate particle size. The method further comprises subjecting the waste slurry to energy emanating from an energy source. The energy source thereby transfers energy to the waste slurry to substantially reduce the agglomerate particle size. Substantially reduce means that the agglomerate is size is reduced such that the waste slurry is free to flow through the drain.

Abstract: A distortion analyzer for generating a distortion signal based on an input signal. For example, the distortion signal may be generated by adding a first signal corresponding to the entire spectrum of the input signal to a second signal corresponding to a low-frequency component of the input signal and then subtracting from the result of addition a third signal corresponding to a specific frequency band of the input signal. The effect of polarization mode dispersion that an optical signal experiences as it propagates through an optical transmission fiber may be compensated for at a receiver using a birefringent compensator, in which the distortion analyzer continuously examines the signal outputted by the compensator and supplies the distortion signal to the compensator, which causes the compensator to reduce the effect of such polarization mode dispersion based on the level of the distortion signal.

Abstract: A copying logic block for, and a method of, programming an FPGA and a modular music synthesis processor incorporating the copying logic block or the method. In one embodiment, the copying logic block includes: (1) a block receiver that receives an instantiable logic block via a programming port of the FPGA and (2) a block instantiator, coupled to the block receiver, that creates multiple instantiations of the instantiable logic block within the FPGA in response to a command received via the programming port without requiring each of the multiple instantiations to enter the FPGA via the programming port.

Abstract: The present invention consists of a method and apparatus for measuring first and higher order PMD vectors in optical fibers. For each first-order PMD vector determination, two distinct polarization states are sequentially injected into an optical device under test for each of a pair of frequencies &ohgr; and &ohgr;+&Dgr;&ohgr;f. A Stokes vector s1 representing the first polarization state must not be parallel or anti-parallel to a Stokes vector sa representing the second polarization state, but the relative angle between s1 and sa need not be known. The frequency interval &Dgr;&ohgr;f is large to obtain a high signal-to-noise ratio. Thus, four light beams are injected, the first at frequency &ohgr; and polarization s1, the second at frequency &ohgr; and polarization sa, the third at frequency &ohgr;+&Dgr;&ohgr;f and polarization s1, and the fourth light at frequency &ohgr;+&Dgr;&ohgr;f and polarization sa.

Abstract: Methods and apparatus for estimating mobile location in a wireless communication system including a plurality of base stations. In a base-to-mobile embodiment, the system base stations periodically transmit location signals to mobile stations during a system-wide blank-and-burst interval during which normal wireless communications are suspended. The interval is made sufficiently short that disruption to normal operation is negligible. Each base station transmits a distinct location signal which can be identified by a mobile station as associated with a particular base station. A given mobile station for which a location estimate is to be generated detects location signals from at least three of the system base stations. The detected location signals are used to generate differential path delay measurements which may be further processed in accordance with a triangulation technique to generate an estimate of mobile location.

Abstract: A system for, and method of, ensuring serialization of lazy updates in a distributed database described by a directed acyclic copy graph. In one embodiment, the system includes: (1) a forest construction module that creates a forest having trees and edges from the directed acyclic copy graph and (2) a propagation module, associated with the forest construction module, that employs the edges of the forest to propagate the lazy updates among replicas in the distributed database and ensure the serialization.

Abstract: A finite state machine that implements the ETSI Intelligent Network Capability Set 1 for INAP protocol using a first finite state machine connected to a second finite state machine. To accomplish this implementation, the first finite state machine receives inputs and makes initial state transition choices. Once the first finite state machine has made an initial choice, the second finite state machine checks to see if the first finite state machine has transitioned to the appropriate state and, if it has not, give feedback to the finite state machine to the appropriate state. Once the appropriate state is reached, the outputs of the first finite state machine are valid and available. The finite state machines may be realized as physical logical devices or virtually using VFSM technology.

Abstract: We disclose a method for routing a set of demands in a ring network that comprises nodes interconnected by directed links, in which each demand may be routed clockwise or counterclockwise. According to our method, a linear program is solved to obtain a set of routing variables that minimize an objective function. Each routing variable corresponds to a respective one of the demands, and has a value, exemplarily, on the closed interval from 0 to 1. A value of 1 signifies, e.g., clockwise routing, and a value of 0 signifies counterclockwise routing. The objective function describes the value of a load, defined on each link and maximized over all links of the network, so that a solution of the linear program provides a minimum value of the maximized load. The method further comprises rounding the routing variables so that the value of each routing variable falls at 1 or 0. This rounding is carried out such that the maximized load does not exceed the previously-obtained minimum value of the maximized load.

Abstract: Resonances in cross-phase-modulation (CPM) impairment occur in wavelength-division-multiplexed (WDM) transmission systems, having multiple equal dispersion-length amplifier spans, when channels have an integral number of bit walk-throughs per amplifier span. The CPM resonances are reduced by mis-matching the amplifier span lengths (and/or dispersion in each span) so an integral number of bit walk-throughs do not occur in successive amplifier spans. The CPM resonances are reduced by adding different lengths of dispersion-compensating fiber to each span, using different modulation bit rates and/or clock phase delay for each channel, and using different wavelength-selective clock phase delays for each channel.

Abstract: A technique for regulating a DC source voltage extracts charge from a capacitor to maintain a fixed voltage across an output load, the voltage across the output load being smaller than the DC source voltage. An output voltage that indicates a voltage drop across the capacitor is sensed and compared to a voltage reference source. The on-time of a switch, connected in series with a transformer, the series combination connected across the capacitor, is varied based on the result of the comparison, thereby controlling the voltage across the capacitor and the output voltage.

Abstract: A novel method is disclosed to create elongated apertures from circular holes provide a snap fit of square or rectangular tabs or tangs without requiring special tooling or milling. According to the method of the invention, at the intersection of the circular holes, points of engagement are formed that hold the square or rectangular tab in place. The size and spacing of the intersecting circular holes determine the depth of the points of engagement and the size of the square or rectangular tab that can be held.

Abstract: A method of modeling erbium doped fiber (“EDF”) for use in erbium doped fiber amplifiers (“EDFA”). The EDF has a length and a fractional population density of erbium ions in an excited state. Since the EDF supports N channels, the power propagation along the EDF is characterized by N+1 differential equations as a function of the direction of propagation, z, of the channels along the length l of the EDF and the time t. By applying an average inversion model to a spatially averaged inversion level of the erbium ions in the fiber, the N+1 partial differential equations are reduced to a single ordinary differential equation. This allows an analytical solution at the boundary and initial conditions of the fiber so that an expression for the power of the signal propagating along the fiber can be obtained. With this expression, the single equation can be solved analytically for the inversion level at any point along the EDF.

Abstract: The wireless CDMA system includes a base station which generates a configuration channel as one of the forward control channels. The message slots in the configuration channel only include overhead messages. The base station also generates at least one other forward control channel, but these other forward control channels do not need to include overhead messages in any of their message slots. The mobiles in the system determine the location of the configuration channel from information in a sync channel generated by the base station. By camping onto the configuration channel, a mobile can quickly obtain the overhead parameters in the overhead messages. Because obtaining overhead parameters and keeping an updated version of the overhead parameters is an important factor in overall performance, the significant decrease in overhead message access time provided by the provision of the configuration channel greatly improves performance.

Abstract: A wireless communication device comprising a signal processing device coupled to a cluster of multiple port antennas that can simultaneously transmit and/or receive communication signals. The cluster of antennas operates within a frequency band having maximum frequency f, and at least a pair of the antenna ports is placed in a volume of space whose longest linear dimension is &lgr;/3 or less where &lgr; is equal to c/f. During operation of the antenna cluster, the radiation patterns from different antennas have main lobes that point in different directions and have correlations of 0.7 or less with respect to each other.

Abstract: A system and apparatus for controlling an appliance situated within a premises such as a home or office has a premises controller for receiving and storing appliance control information. The premises controller includes a wireless transmitter for generating and transmitting a packet of appliance control information to an appliance controller based on the stored appliance control information. In one aspect of the invention, the appliance controller is spaced from the premises controller but within range of the generated packet transmission for interfacing with the premises appliance. The appliance controller further includes a packet receiver for receiving the packet of control information. In one aspect of the invention, the premises controller has a microprocessor. An infrared pulse generator is operatively connected to the microprocessor and generates and transmits an infrared pulse code to the appliance.

Abstract: A test system for a evaluating a digital signal link includes a data signal generator, a data signal receiver, a digital signal link to be tested and a test interference signal injection (TISI) network connected as part of the digital signal link. The TISI network includes a data signal input port for receiving digital data signals generated by the data signal generator, a data signal output port for providing the digital data signals to the data signal receiver, and a controlled impedance data signal path carrying the digital data signals between the data signal input port and the data signal output port. An interference signal input port receives interference signals over a range of frequencies from an interference signal generator. One or more directional couplers directionally couple the interference signals into the data signal path toward either the data signal output port or the data signal input port at an impedance that substantially matches the impedance of the digital signal link.

Abstract: Dual concentric core fiber is used for optical communication. Inbound messages lying in a first wavelength channel are received from a terminal portion of the fiber, and outbound messages lying in a second such channel are injected into the terminal portion. The optical fiber has at least one annular portion surrounding a central core portion. The inbound messages are received from the annular portion, and the outbound messages are injected into the central core portion. Alternatively, the inbound messages are received from the central core portion, and the outbound messages are injected into the annular portion.