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. 06, 2001
Filed:
Dec. 21, 1999
Applicant:
Inventor:
Thomas Hornak, Portola Valley, CA (US);
Assignee:
Agilent Technologies, Inc., Palo Alto, CA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03K 5/00 ;
U.S. Cl.
CPC ...
H03K 5/00 ;
Abstract
A polyphase filter passes a desired frequency and attenuates an image frequency in many communication systems. The invention is an error correction circuit that compensates the polyphase filter for low open loop gain operational amplifiers. When multiple polyphase filters are used in communication circuits on a single integrated circuit (IC), the open loop gain of the operational amplifiers is limited by the IC's ability to dissipate power. The error correction circuit reduces the dependency of the polyphase filter performance on the low open loop gain of its operational amplifiers and hence, on temperature and IC process parameters.