The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 17, 2001
Filed:
Sep. 28, 1999
Donald W. Becker, Rancho Santa Fe, CA (US);
William E. L. Leigh, Del Mar, CA (US);
Tachyon, Inc., San Diego, CA (US);
Abstract
A method and apparatus for digitally demodulating QPSK signals includes a first portion in which the digitally sampled data burst is resampled with a plurality of predetermined timing hypotheses. The timing offset is determined according to an analysis of the resampled data. The digitally sampled data burst is then resampled according to the timing estimation. Modulation of the resampled data burst is then removed by twice squaring the complex I/Q pairs. The data with the modulation removed is then subjected to a Chirp-Z Transform to move the data into the frequency domain. The highest spectral power is used to determine the frequency offset. The phase offset is determined and the resampled data burst is derotated and dephased according to the phase offset and the frequency offset.