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:
Dec. 04, 2012
Filed:
Sep. 28, 2009
Kurt E. Sundstrom, Woodinville, WA (US);
Paul Dietrich, Seattle, WA (US);
Christopher J. Diorio, Shoreline, WA (US);
Andrew Friefeld, Redmond, WA (US);
Kurt E. Sundstrom, Woodinville, WA (US);
Paul Dietrich, Seattle, WA (US);
Christopher J. Diorio, Shoreline, WA (US);
Andrew Friefeld, Redmond, WA (US);
Impinj, Inc., Seattle, WA (US);
Abstract
An RFID reader uses an adaptive filter to mitigate the effects of colored noise in tag reply signals. The adaptive filter may be a linear equalizer, a linear-predictive canceller, or a decision-feedback equalizer. The adaptive filter estimates the colored noise portion of the signal received from the tag and removes the noise estimate from the tag signal. The adaptive filter bases its noise estimate on the difference between a desired signal and a portion of the received signal. The reader uses reader-generated training data, a CW signal, and/or portions of the tag reply signal to adapt the filter.