Harmonic correction in phase-locked loops
US6646964B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 27, 2000 |
| Grant date | Nov 11, 2003 |
| Priority date | — |
| Expiry date | Mar 27, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L2207/14
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.