Shanmugavel Sivagnanavelu

US Patent:

8259874, Sep 4, 2012

Filed:

Jul 31, 2009

Appl. No.:

12/533741

Inventors:

Ronggang Qi - Ashburn VA, US
Christopher D. Gregory - Potomac Falls VA, US
Baoyan Ding - Rockville MD, US
Shanmugavel Sivagnanavelu - Bristow VA, US

Assignee:

VT Idirect, Inc. - Herndon VA

International Classification:

H03D 1/00

US Classification:

375343

Abstract:

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.