Abstract: A radio communication device, which transmits or receives a signal at a predetermined carrier frequency. The device includes a reference oscillator, which generates a clock frequency having a clock frequency error relative to a specified frequency thereof, a processor, which estimates the clock frequency error and parses the error to determine coarse and fine error correction components, at least one frequency synthesizer, which responsive to the clock frequency and to the coarse error correction component, generates a partially corrected frequency having a residual frequency error, which partially corrected frequency is applied to process the signal and baseband processing circuitry, which applies the fine error correction component to process the signal so as to correct the residual frequency error.

Abstract: A method for conducting an improved approximated maximum likelihood decoding on a received signal on a receiving side, in the presence of a co-channel interference.

Abstract: A receiver including a signal reception unit, for receiving a signal from a dynamically fading channel, a demodulator, connected to the signal reception unit, for demodulating the received signal, thereby producing a demodulated signal therefrom, a quantizing processor, connected to the demodulator and to the signal reception unit, for analyzing the received signal and for quantizing the demodulated signal, thereby producing a quantized signal, and a decoder, connected to the quantzing processor, for decoding the quantized signal, wherein the quantizing processor normalizes the demodulated signal according to the estimated fading of the received signal.

Abstract: Methods are presented for reducing the processing required for CELP speech encoders which have multiple fixed stochastic codebook subframes corresponding to a single adaptive codebook subframe. The search for the optimum excitation vector in the fixed stochastic codebook requires calculating terms involving correlation of the target speech sample and the fixed stochastic codebook excitation vector as well as energy terms involving only the fixed stochastic codebook excitation vector, and for this class of CELP encoders it is possible to simplify the calculations to reduce their complexity and to make advantageous use of an adaptive energy lookup table. In addition, linear interpolation may be employed to estimate values for the adaptive energy lookup table and further reduce the computational burden.

Abstract: Method and apparatus for efficiently producing a delayed version of a maximum length sequence output from a linear feedback shift register. Polynomial (vector) exponentiation is performed instead of matrix exponentiation to calculate the mask coefficients which yield the delayed sequence from the linear feedback shift register. Polynomial (vector) operations are much simpler and faster than the corresponding matrix operations and require substantially less circuitry and computational effort. Modulo exponentiation of polynomials is done by repeated squaring and shifting, and a division circuit built on a linear feedback shift register is provided to perform an efficient modulo squaring of polynomials.

Abstract: A keyword recognition system for speaker dependent, dynamic time warping (DTW) recognition systems uses all of the trained word templates in the system, (keyword and vocabulary), to determine if an utterance is a keyword utterance or not. The utterance is selected as the keyword if a keyword score indicates a significant match to the keyword template and if the keyword score indicates a better match than do the entirety of scores to the vocabulary word templates.

Abstract: A pattern recognition system and method is disclosed. The method includes the steps of a) providing a noisy test feature set of the input signal, a plurality of reference feature sets of reference templates produced in a quiet environment, and a background noise feature set of background noise present in the input signal, b) producing adapted reference templates from the test feature set, the background noise feature set and the reference feature sets and c) determining match scores defining the match between each of the adapted reference templates and the test feature set. The method can also include adapting the scores before accepting a score as the result. The system and method are described for both Hidden Markov Model (HMM) and Dynamic Time Warping (DTW) scoring units. The system performs the steps of the method.