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. 13, 2010
Filed:
Sep. 17, 2007
Hyeon Min Bae, Champaign, IL (US);
Naresh Ramnath Shanbhag, Champaign, IL (US);
Jonathan B. Ashbrook, Homer, IL (US);
Hyeon Min Bae, Champaign, IL (US);
Naresh Ramnath Shanbhag, Champaign, IL (US);
Jonathan B. Ashbrook, Homer, IL (US);
Finisar Corporation, Sunnyvale, CA (US);
Abstract
A variable gain amplifier and offset cancellation loop circuit and methods for tracking and correcting DC offset errors that may vary in accordance with the gain of the variable gain amplifier. The circuit is designed to provide tracking of rapid changes in the offset error while maintaining a desired overall frequency response of the combined variable gain amplifier and offset loop. The offset loop cancellation circuit has a wide enough bandwidth to allow the offset cancellation loop to track rapid changes in offset errors that result from rapid changes to the amplifier's gain setting. A control circuit is provided to prevent the large offset cancellation loop bandwidth from having a detrimental effect on the amplifier's overall bandwidth when the amplifier is set to high levels of forward gain by adjusting the offset cancellation loop gain as the forward gain of the amplifier is altered.