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:
Aug. 09, 2005
Filed:
Oct. 30, 2003
Daniel Y. Abramovitch, Palo Alto, CA (US);
Michael C. Fischer, Palo Alto, CA (US);
Joshua N. Hogan, Los Altos, CA (US);
Carl P. Taussig, Redwood City, CA (US);
Daniel Y. Abramovitch, Palo Alto, CA (US);
Michael C. Fischer, Palo Alto, CA (US);
Joshua N. Hogan, Los Altos, CA (US);
Carl P. Taussig, Redwood City, CA (US);
Hewlett-Packard Development Company, L.P., Houston, TX (US);
Abstract
Correction for harmonic disturbances on rotating storage media in a phase-locked loop. The effects of harmonic disturbances in a phase-locked loop are reduced by employing harmonic correction. Harmonic correction may be present in the loop at all times, or may be switched in once the loop has achieved phase lock. Disturbance within the loop bandwidth is corrected using additional integrating pole or a bump (resonant) filter. Disturbance outside the loop bandwidth is corrected using low pass or a notch (anti-resonant) filter. Alternately, a canceling signal may be generated and added as a feedforward signal. A repetitive control scheme uses a filtered version of the residual errors on previous media rotations as a feedforward signal to cancel harmonic effects.