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. 02, 1996
Filed:
Oct. 14, 1994
Andrew MacDonald, Damascus, MD (US);
Richard Clewer, Ijamsville, MD (US);
Janavikulam Anandkumar, Gaithersburg, MD (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
A method and apparatus for use in estimating phase error in a phase-modulated carrier. The method and apparatus of the present invention may be embodied in a phase-error-estimator circuit which is typically incorporated into a demodulator of a digital communications receiver. In general, the phase-error-estimator circuit receives the I and Q components of a phase-modulated signal, and outputs an estimate of the phase error, if any, in the phase-modulated carrier signal associated with the received I and Q. Preferably, the phase-error-estimator circuit includes an index/polarity generator circuit coupled to a look-up table. The index/polarity generator receives I and Q and maps them onto a reduced range of phase angles represented by values X and Y. X and Y are fed to a reduced and substantially triangular look-up table which outputs the stored phase-error-estimate for the particular X and Y inputs.