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:
Jul. 29, 2008
Filed:
Jul. 11, 2005
Sameh S. Rezeq, Dallas, TX (US);
Dirk Leipold, Dallas, TX (US);
Robert B. Staszewski, Garland, TX (US);
Chih-ming Hung, McKinney, TX (US);
Sameh S. Rezeq, Dallas, TX (US);
Dirk Leipold, Dallas, TX (US);
Robert B. Staszewski, Garland, TX (US);
Chih-Ming Hung, McKinney, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A novel method and apparatus for a negative contributive offset compensation mechanism for a transmit buffer adapted to compensate for the positive offset generated by higher order sigma-delta modulators used to amplitude modulate the transmit buffer. The positive outputs from the sigma-delta modulator are processed differently than the negative outputs. The inverters associated with the negative outputs in the sigma-delta modulator are removed and the clock signal used to drive the transistors corresponding to the negative outputs is negated or shifted 180 degrees from the clock used to drive the transistors corresponding to the positive outputs. A non-inverted version of the clock is used with the positive outputs and an inverse clock is used with the negative outputs. Use of the inverse clock causes a negative contributive offset to be generated that is added on the second half cycle of each clock. The result is an offset compensated RF output signal having zero offset.