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:
Mar. 05, 1996
Filed:
Dec. 06, 1993
Lansing M Carson, Chandler, AZ (US);
Robert J Burdge, Mesa, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A data communication receiver (10) uses a decision feedback demodulator (32) to remove data from a received signal. Quadrature components of the received signal define a received phase. The received phase is rotated (46) by an amount predicted to compensate for phase and frequency errors. After this rotation, a decision circuit (52) determines the modulation phase for a current symbol. A phase rotator (64) compares the modulation phase with the received phase to generate a measured phase error for the symbol. This measured phase error and measured phase errors from past symbols are averaged in a combination circuit (80) to produce a phase estimate. The past measured phase errors are also processed to determine the amount of change in measured phase error that has occurred over a number of symbols. This processing yields a frequency estimate. A phase rotator (94) merges the frequency and phase estimates for use in compensating a current received phase.