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:
Oct. 09, 2007
Filed:
Aug. 27, 2003
Samuel M. Babb, Fort Collins, CO (US);
Jeffrey S. Weaver, Fort Collins, CO (US);
James L. Yost, Fort Collins, CO (US);
Garland E. Lee, Windsor, CO (US);
Peter M. Piotrowski, Fort Collins, CO (US);
Samuel M. Babb, Fort Collins, CO (US);
Jeffrey S. Weaver, Fort Collins, CO (US);
James L. Yost, Fort Collins, CO (US);
Garland E. Lee, Windsor, CO (US);
Peter M. Piotrowski, Fort Collins, CO (US);
Hewlett-Packard Development Company, L.P., Houston, TX (US);
Abstract
A method for reducing commutation-related acoustic noise in a fan system is provided. A constant frequency periodic signal is generated and a fan commutation event is synchronized with a zero level value of the constant frequency periodic signal. A system for controlling a direct current fan is provided. The system comprises a signal generator adapted to produce a periodic signal of a constant frequency and a phase-locked loop. A zero level value of the periodic signal is synchronized with a commutation event of the fan.