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. 27, 2007
Filed:
Sep. 01, 2004
Michael Hendrikus Kouwenhoven, Zoetermeer, NL;
Arie Van Staveren, Hazerswoude-dorp, NL;
Michael Hendrikus Kouwenhoven, Zoetermeer, NL;
Arie van Staveren, Hazerswoude-dorp, NL;
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A method and circuit to eliminate an offset noise, which may be produced at or near DC (zero Hertz) in an analog, linear multiplier, is described. An input signal is chopped (converted to another frequency) by a first chopper, shifting a frequency of the input signal such that the multiplier output signal is shifted away from DC. An output signal of the multiplier is subsequently chopped again by a second chopper employing the same chopping frequency as the first chopper. This converts a frequency of the output signal to a desired frequency at or near DC. The double chopping also shifts the offset noise produced by the multiplier to a frequency, that is higher than the frequency of the output signal. The offset noise can then be removed by a low-pass filter leaving the output signal without the offset noise.