Abstract: Detecting attempted intrusions in a telecommunications signaling network and assessing the vulnerability of the network to attempted intrusions. Intrusion rules are applied to received messages in the network in real-time, using a known protocol for the network, in order to detect anomalies tending to indicate an attempted intrusion. In order to assess the vulnerability of the network, vulnerability rules are applied to rankings of particular parameters relating to elements in the network. The rankings provide an indication of susceptibility of a network element to an attempted intrusion relative to other network elements.

Abstract: Methods and systems consistent with the present invention intercept and monitor signals of any type associated with a target telephone number in a communications network such that the interception and the monitoring are undetectable. Such methods and systems configure a network by provisioning a route to a collection node in the network, defining a first trigger for intercepting a signal associated with the target telephone number, and by defining a second trigger for routing the intercepted signal on the provisioned route to the collection node. The methods and systems then monitor the signal at the collection node by intercepting the signal based on the first trigger and routing the intercepted signal to the collection node based on the second trigger.

Abstract: A scalable multiplier architecture for the Galois field GF(2k) is implemented in a programmable circuit. This architecture may be used in an implementation of public-key cryptosystems which use programmable multipliers in large Galois fields. This architecture is also fine grain scalable in both the time and the area (or logic) dimensions.

Abstract: Non-planar propellers or windmill blade assemblys are proposed which have tips that are curved to point in the same direction as the axis of rotation of the propeller. This non-conventional design results in a stronger, stiffer, and more efficient propeller or windmill.

Abstract: The presence of interfering continuous-wave signals are automatically detected in the demodulated output of a quadrature amplitude modulation data communications receiver. The transmitter is re-tuned in order to avoid the detected interferer. Statistical information concerning the received signal is accumulated at a receiver and is analyzed to determine whether a reduction in the received bit-error-rate is due to the presence of an interferer. If an inteferer is determined to be present within the signal transmission bandwidth, then the potentially available transmission band is spectrum analyzed to find a new portion of that band in which the signal can be transmitted free of the interferer. The results of the statistical analysis and the spectral analysis are conveyed back to the transmitter which then readjusts the transmission parameters and forwards the new parameters to the receiver.

Abstract: This disclosure describes systems and methods for processing voice data for secure transmission and secure receipt over a network, such as the Internet. The systems and methods include the processing of analog voice and digital information, including conversion of a voice signal into digital information (or of digital information into a voice signal) and transmission of digital information representing voice data over a network. The analog-to-digital conversion (and digital-to-analog conversion) includes coding and decoding digital information according to voice coding techniques and encrypting and decrypting digital information according to encryption techniques. The transmission of the digital information includes creation of a secure voice frame.

Abstract: A method and apparatus are described for adaptively predistorting a signal before it is transmitted by a transmitter in order to compensate for nonlinearities which are introduced. Statistical information regarding the received signal is accumulated at a receiver, and is preferably transmitted back to the transmitter for processing. The processing includes a constellation analysis to determine the distortion characteristics of the signal, which may include bias, gain imbalance, lock and quad angle errors, and nonlinear distortions including AM-AM and AM-PM conversion effects, with all of these phenomena occurring anywhere in the transmitter-channel-receiverchain. From analysis of the statistics of the distortions in the received signal constellation, adjustments are made in the transmitter and/or receiver parameters.

Abstract: An algorithm for emitter identification of a transmitting platform using spectral energy analysis, and a system utilizing said algorithm, wherein said algorithm processes audio signals from transmission data using a fast fourier transform, detecting gaps in said processed transmission data. It then extracts spectral features consisting of normalized energy per unit frequency from said gaps. The algorithm and system then proceed to execute a decision function based on said extracted characteristic features to identify the platform of said transmitter based on said features. A second algorithm, which may be executed in parallel with the first by said system, processes the same transmission data to detect transmission activity on a radio channel in the audio frequency range, and to detect the boundaries of transmitter keyclicks at the beginning and end of said transmission.

Abstract: An algorithm for emitter identification of a transmitting platform using microphone keyclick analysis, and a system utilizing said algorithm, wherein said algorithm processes audio signals to detect transmission activity on a radio channel in the audio frequency range, detects the boundaries of transmitter keyclicks at the beginning and end of said transmission; extracts keying envelopes from said detected keyclick boundaries; and analyzes said keying envelopes to extract features characteristic of said keyclicks. The algorithm and system then proceed to execute a decision function based on said extracted characteristic features to identify the platform of said transmitter based on the features of said keyclick. A second algorithm, which may be executed in parallel with the first by said system, processes said transmission data using a fast fourier transform, detecting gaps in said processed transmission data.

Abstract: A method and apparatus are described for adaptively pre-emphasizing signals transmitted over a stable but occasionally varying transmission medium such as a very-high-speed digital subscriber line (VDSL) signal, before it is transmitted by a transmitter, in order to compensate for frequency distortion that is introduced by the VDSL transmission line. At system start up, or whenever the parameters or configuration of the line are changed, the the line termination transceivers at both ends of the transmission line exchange calibration signals to measure the attenuation-versus-frequency curves of the line in both directions. Thereafter, whenever the signal transmission band is to be changed in either direction, the transmitter for that direction uses the measured attenuation curve for the line to calculate and design a set of filter coefficients for an adjustable pre-emphasis filter.

Abstract: A programmable signal decoder processes incoming signals using any one of several predefined decoding schemes. The signal decoder is programmed to perform the desired decoding operations by downloading configuration data representative of the decoding scheme from a data memory to programmable logic in the signal decoder. Programmable metric tables provide set mapping. A generic four-level decoder structure includes two levels that are programmable Viterbi decoders, one level that is a Wagner decoder and another level that provides free bit selection operations. The four levels are combined, as needed, to implement two-dimensional, four-dimensional, multi-level and other coded modulation formats.

Abstract: A rolling-element clutch assembly including a first race member, a second race member and a plurality of rolling elements. The first race member defines a first race surface having a first ratchet surface portion. The second race member defines a second race surface having a second ratchet surface portion. The first race surface and the second race surface define a raceway therebetween. A plurality of rolling elements are disposed in the raceway. The rolling elements provide rolling support between the first race member and the second race member when the first race member moves in a first direction relative to the second race member. At least one of the plurality of rolling elements engages the first and second ratchet surface portions when the first race member moves in a second direction relative to the second race member.

Abstract: An improved digital bi-directional communications transceiver in which the upstream and downstream portions of the frequency spectrum are allocated different bandwidths and positioned at different locations on the frequency spectrum in response to transmission line conditions and impairments such as system provisioning, background noise, radio frequency interference (RFI), crosstalk and reflected signals. The movement of the upstream and downstream carrier frequencies are elastic in that they may be adjusted in near real-time involving methods for determining the signal quality parameter(SQP) of the received signal. The SQP is used to estimate the bit error rate (BER) margin on the received data and also takes into account the total signal to interference ratio (SIR), where the interference includes crosstalk, RFI, and residual echo from the neighboring upstream or downstream channel.

Abstract: A simplified symbol lock detector which uses T/2 spaced signal samples in conjunction with an interpolator to approximate the T/4 shifted signal samples used by conventional symbol lock detectors. The approximated T/4 shifted signal samples are processed by a phase detector prior to input to a threshold detector which indicates proper symbol lock if the lock signal exceeds a predetermined threshold.

Abstract: A processing system and method identifies materials present in a pixel of a multispectral or a hyperspectral image. Underlying data models representing spectral endmembers or materials of interest and model based relationships are used to identify the materials. The processing system and method provide a technique that detects, unmixes, and classifies spectral signatures for terrain categorization and object identification.