Vt Idirect, Inc.

Baoyan Ding

Ronggang Qi

Christopher Donald Gregory

Paul M Wayner

Shanmugavel Sivagnanavelu

A device and method for estimating a bias in a frequency estimate of a received signal. Circuitry generates a first signal including a number of sample-blocks, wherein the first signal is shifted in frequency from the received signal by a first frequency shift. Based on the first signal, a second signal and a third signal are generated, by shifting a frequency of each of the samples of the first generated signal by a second frequency shift and a third frequency shift, respectively. For each generated signal, a variance for each sample-block is computed. An average variance of the computed sample-block variances is further calculated and a bias of the received signal is determined as one of the first frequency shift, the second frequency shift, and the third frequency shift, corresponding to the generated signal having the smallest calculated average variance.

Apparatus and method for frequency estimation ambiguity removal of a burst signal

A device and method for unwrapping phase samples of a burst signal. The device generates a set of vectors including phase samples. A first mean and a first variance of the vectors is computed, and a set of unwrapped phase samples of the burst signal are computed by rotating phase samples of the vector having a smallest first variance by a first rotation amount. The set of vectors is updated based on a new phase sample and a second mean and a second variance of the updated set of vectors is computed. Differences between unwrapped phase samples and a number of phase samples included in the vector having the smallest computed second variance are computed. A next unwrapped phase sample is generated by rotating the new phase sample by a second rotation amount corresponding to a median value of the computed differences.

Apparatus and method for phase unwrapping of a burst signal

A method of decoding a digitally encoded signal having plural channels includes sampling a transient portion of a master filter mask, storing matched filter coefficients obtained from the sampling, receiving the digitally encoded signal, channelizing the digitally encoded signal into the plural channels, and generating a channel matched filter mask for each one of the plural channels using a subset of the stored coefficients. The method also includes filtering each one of the plural channels, in the frequency domain, based on the channel matched filter mask generated for each of the plural channels. Also disclosed are related methods using a burst reconstruction buffer, per channel distortion equalization, channel estimation and activity monitoring, and noise floor estimation, as well as corresponding apparatuses.

Multicarrier channelization and demodulation apparatus and method

An apparatus and method to optimize recovery of the carrier frequency performs independent optimization of frequency capture range and carrier frequency estimation accuracy. A multi-correlator selects a frequency-shifted version of a signal of interest, extracted from a received signal, to output a coarse frequency-shifted version of the signal of interest. A fine frequency estimator shifts a frequency of the coarse frequency-shifted version of the signal of interest, based on a frequency corresponding to the spectral peak of the coarse frequency-shifted version of the signal of interest, and generates a fine frequency-shifted version of the signal of interest. A fine frequency estimator generates an intermediate frequency estimate and a plurality of phase estimates, based on the coarse frequency-shifted version of the signal of interest, resolves phase ambiguities in the plurality of phase estimates based on the intermediate frequency estimate, and generates a fine frequency-shifted version of the signal of interest.

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Potomac, MD, United States of America

Baoyan Ding