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.

Date of Patent:
Dec. 13, 2005

Filed:

Nov. 08, 2002
Applicants:

Gregory S. Rawlins, Heathrow, FL (US);

Kevin Brown, Clermont, FL (US);

Michael W. Rawlins, Lake Mary, FL (US);

David F. Sorrells, Middleburg, FL (US);

Inventors:

Gregory S. Rawlins, Heathrow, FL (US);

Kevin Brown, Clermont, FL (US);

Michael W. Rawlins, Lake Mary, FL (US);

David F. Sorrells, Middleburg, FL (US);

Assignee:

ParkerVision, Inc., Jacksonville, FL (US);

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04B001/10 ; H04B001/06 ; H03F003/26 ;
U.S. Cl.
CPC ...
Abstract

A filter module for reducing a DC offset voltage in a radio frequency communication channel is described. A first capacitor is coupled between a first differential input node and a first differential output node. A second capacitor is coupled between a second differential input node and a second differential output node. An active variable resistor is coupled between the first differential output node and the second differential output node. The active variable resistor receives a control signal. The control signal adjusts the value of the active variable resistor, which adjusts the frequency response of the filter module. The rate at which the filter module reduces DC offset voltages is thereby adjusted. The filter module is also adaptable to single-ended applications.


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