Abstract: A compressive sensor array (CSA) system and method uses compressive sampling techniques to acquire sensor data from an array of sensors without independently sampling each of the sensor signals. In general, the CSA system and method uses the compressive sampling techniques to combine the analog sensor signals from the array of sensors into a composite sensor signal and to sample the composite sensor signal at a sub-Nyquist sampling rate. At least one embodiment of the CSA system and method allows a single analog-to-digital converter (ADC) and single RF demodulation chain to be used for an arbitrary number of sensors, thereby providing scalability and eliminating redundant data acquisition hardware. By reducing the number of samples, the CSA system and method also facilitates the processing, storage and transmission of the sensor data.

Abstract: A compressive sensor array (CSA) system and method uses compressive sampling techniques to acquire sensor data from an array of sensors without independently sampling each of the sensor signals. In general, the CSA system and method uses the compressive sampling techniques to combine the analog sensor signals from the array of sensors into a composite sensor signal and to sample the composite sensor signal at a sub-Nyquist sampling rate. At least one embodiment of the CSA system and method allows a single analog-to-digital converter (ADC) and single RF demodulation chain to be used for an arbitrary number of sensors, thereby providing scalability and eliminating redundant data acquisition hardware. By reducing the number of samples, the CSA system and method also facilitates the processing, storage and transmission of the sensor data.

Abstract: Implementations for the synchronization of a spread spectrum signal in the presence of delay and frequency uncertainty. According to one embodiment, there is a signal processing technique that combines coherent integration with a Fast Fourier Transform (FFT). Coherent integration with the direct sequence code is achieved through the use of shift registers, code modulators, and integrators, and applied to subsequences of the spreading code. Subsequences can then be combined via an FFT to achieve further coherent integration and to simultaneously deal with frequency uncertainty.

Abstract: A method and system begin at a random node of a trellis model having a set of at least two axes, wherein one axis corresponds to time and a second axis corresponds to frequency, a set of M states, corresponding to a set of all possible frequencies that may be transmitted by the system, and branches leaving each state, that terminate at allowable transmit frequencies for a next frequency hop. The number of branches leaving each state is dependent on the number of encoded bits per hop. Next, B bits of data are passed to a buffer, where B is the number of bits that will be transmitted per frequency hop. The method and system then combine the B bits of data with information for previously selected frequencies to select a current frequency, transmit the selected frequency, and feedback the currently selected frequency information to be used as previously selected frequency information when selecting a next frequency.

Abstract: A method and system begin at a random node of a trellis model having a set of at least two axes, wherein one axis corresponds to time and a second axis corresponds to frequency, a set of M states, corresponding to a set of all possible frequencies that may be transmitted by the system, and branches leaving each state, that terminate at allowable transmit frequencies for a next frequency hop. The number of branches leaving each state is dependent on the number of encoded bits per hop. Next, B bits of data are passed to a buffer, where B is the number of bits that will be transmitted per frequency hop. The method and system then combine the B bits of data with information for previously selected frequencies to select a current frequency, transmit the selected frequency, and feedback the currently selected frequency information to be used as previously selected frequency information when selecting a next frequency.

Abstract: This speech recognizer concatenates a string of reference isolated-words for comparison with the unknown string of connected-words. The invention includes a level-building (LB) algorithm, "level" implying a location in a sequence of words. A constrained endpoint dynamic-time-warp algorithm, in which the slope of the warping function is restricted between 1/2 and 2, is used to find the best alignment between an unknown continuous-word test pattern, and a concatenated sequence of L reference patterns. Properties of the LB algorithm include: modification of the references; back-track decision logic; heuristic selection of multiple candidates, and syntax constraints. As a result, the processing required is less than two-level dynamic-program-matching and sampling algorithms.