Abstract: There is provided a method and a system for determining the concentration of chromophores and reconstructing images in turbid media, such as animal tissues, using a continuous wave optical approach. In particular the approach is based on measurements of attenuation signals and the calculation of concentrations of chromophores using a predetermined scatter law. The system comprises a continuous wave photon migration model calculator coupled to an optical source and detector for estimating concentrations of chromophores and scatter parameters used in image reconstruction.

Abstract: Performance monitoring and equalization of DWDM optical links equipped with optical add/drop multiplexers (OADMs) at one or more sites is effected by selecting a direction of transmission and the end sites from the point of view of equalization. Performance monitoring and equalization of DWDM optical links equipped with optical add/drop multiplexers (OADM) is presented in this application. This approach in involves conceptually converting a multiple ends system to a “two-end” system with analogous channels (AC) to simplify the network management and equalize the DWDM channel performance. All analogous channels are treated as originating at a source analogous end and terminating at a destination analogous end for the purpose of equalization. The input power for all ACs, is adjusted at the source AE to obtain equal channel performance at the destination AE.

Abstract: A protection switching technique associated with an OP-n sublayer of a communications network is presented. Among the advantages presented by this protection switching technique of the present invention are the ability to provision logical protected subnetworks that are not constrained to the topology of the physical line systems, the ability of a single high capacity link system to support multiple protected subnetworks, the ability to provide complex protection schemes such as m:n protection within the physical link system.

Abstract: A high speed D/A converter includes a phase aligner, and a vector summation block. The phase aligner operates to ensure precise phase alignment between corresponding bits of a parallel N-bit digital signal having a data rate of at least 2 GHz. The vector addition block performs a vector addition of the phase-aligned bits of the parallel N-bit digital signal. Each bit of the parallel N-bit digital signal can be weighted to ensure a correct additive contribution to the analog signal level appearing at the output of the D/A converter. Vector addition of the weighted bits can be accomplished using a microwave signal combiner network in the form of either a multistage parallel cascade of impedance matched junctions, or a linear cascade of junctions.

Abstract: A method and apparatus for using sacrificial bits in a data stream to adjust sampling parameters for the data stream is described. The sacrificial bits are a predetermined sequence of a predetermined length. The sampling parameters are perturbed during transmission or reception of the sacrificial bits in order to provide information useful in adjusting the sampling parameters of the apparatus. Adjustment is accomplished by computing a bit error rate during the perturbing of sampling parameters in order to probe edges of an eye closure of the detected signal. The advantage is faster homing on optimal sampling parameters with little sacrifice of transmission capacity.

Abstract: Failures within a communications network are compensated for by establishing a set of two or more communications paths across the network between a source node and a destination node. At the source node a status of each one of the set of communications paths is maintained, and the data traffic is load-balanced across those ones of the set of communications paths having an operational status. In the event of failure of a physical network resource, a failure notification message is propagated to the source node, which registers a non-operation status of each path traversing the failed resource. Load-balancing of the data traffic continues across the remaining operational paths. Traffic may be prioritized based on service level agreements and quality of service protection guarantees.

Abstract: A directional coupler for a modem has a high common mode noise rejection characteristic with low transmit signal leakage, and reduced distortion of components mixed with a received signal. A primary filter network is connected to a communications circuit. The primary filter network has an output connected to an input of an amplifier. A feedback network is connected between the input and output of the amplifier. The primary filter network, the amplifier and the feedback network are arranged to provide a virtual ground at the input of the amplifier, and a filter characteristic which attenuates frequencies in the transmit signal band. The advantage is reduced component count while providing excellent transmit signal rejection and reducing received signal distortion.

Abstract: A method and apparatus for remotely updating firmware saved in a FLASH memory of a communication device connected to a network is presented. The FLASH memory is partitioned into at least a first and a second portion. A first firmware load is stored in the first portion. During run-time of the first firmware load, at least a portion of an updated firmware load is transmitted through the network to the communication device. The transmitted portion of the updated firmware load is temporarily stored in a buffer of the communication device. At least a portion of the first firmware load is copied into a random access memory (RAM) of the communication device. Execution, from the RAM, of the copied portion of the first firmware load is triggered. Under control of the copied portion of the first firmware load, the transmitted portion of the updated firmware load is saved to the second portion of the FLASH memory.

Abstract: An Enhanced Communication Services layer is adapted for connection intermediate a content application layer and a transport services layer of a communication network. The content application layer is adapted to generate payload data of a service instance. The transport services layer includes a physical fabric of the communication network and is adapted for end-to-end transport of the payload data across the communication network. The Enhanced Communication Services layer comprises a Contact Agent, an Exchange Agent and a Transport Agent, The Contact Agent is adapted to discover information identifying parties involved in a service instance. The Exchange Agent is responsive to the Contact Agent, and adapted to select, from a network space comprising one or more transport services, a best match set of transport services for the service instance. Finally, the Transport Agent is responsive to the Exchange Agent for engaging the selected set of transport services for the duration of the service instance.

Abstract: This invention relates to fabrication techniques for the creation of new optical elements, an asymmetric (non-reciprocal) diffraction grating and a passive nonlinear optical (visible, microwave, etc.) isolator (diode). It may have potential applications in the field of optical detection (spectrometers) and communications (circulators, wavelength division multiplexing circuits, etc.), etc. One of applications of this proposal is the significant reduction of the noise level in optical communication systems or any other optical systems using laser sources. Another potential interest of these diodes is the fabrication of integrated laser gyroscopes for applications in aviation, etc.

Abstract: In method of controlling an optical amplifier dynamically adapts to both configuration and performance changes of a communications system. An error vector is calculated to indicate a difference between respective detected values and target values of a parameter of a light beam downstream of the optical amplifier. A sensitivity matrix indicative of a sensitivity of the detected parameter value to incremental changes in a control variable of the optical amplifier is calculated. A predicted optimum value of the control variable is then calculated using the error vector and the sensitivity matrix. Calculation of the predicted optimum control variable value can be iterative, with the sensitivity matrix calculated either during each iteration, or at the beginning of each optimization run. As a result, optimization of the amplifier control variables is performed based on a sensitivity matrix that accurately reflects the performance of the amplifier.

Abstract: A system for provisioning a dynamic multicast group over a differentiated services (DS) network includes an a plurality of edge nodes, each of which includes a respective multicast traffic engineering entity. An ingress node is adapted to serve as a source of data traffic of the dynamic multicast group. An egress node is adapted to serve as a sink of the data traffic of the dynamic multicast group. The multicast traffic engineering entity of the egress node is adapted for receiving information respecting a predetermined service level specification (SLS) of the dynamic multicast group; and provisioning a distribution path from the egress node back to the ingress node, on the basis of the received information respecting the SLS.

Abstract: A modular rotatable food tray supported by a vertical support member features tray segments that are easily removable and free standing. Each tray segment has a depending clip that is received in a hub of a bearing for rotatably supporting the tray. The individual tray segments may be removed for filling and cleaning, and segments of different configuration can be used for different purposes. The trays can also be removed for serving away from the support member.

Abstract: A power amplifier receives an input analog signal and generates a corresponding power amplified output analog signal. The power amplifier includes first and second power supply rails, an amplifier circuit, and a switch circuit. The first and second power supply rails are capable of supplying power having respective first and second predetermined levels, and a single predetermined polarity. The amplifier circuit is connected to receive the input analog signal and adapted to generate the output analog signal. Finally, the switch circuit is adapted to selectively connect one of the first and second power supply rails to the amplifier circuit.

Abstract: A method and apparatus for single-ended qualification of subscriber loops for xDSL services is described. The method involves first screening a subscriber loop database record for disqualifying devices or services on the subscriber loop. If none are found, a set of predetermined electrical characteristics of the subscriber loop are derived from information in the database, or directly measured using test equipment at a central office end of the subscriber loop. The electrical characteristics are used to compute an available bandwidth on the subscriber loop for xDSL services. The advantage is the rapid and inexpensive qualification of subscriber loops which reduces response time to potential customer queries and facilitates deployment of xDSL services.