Method and apparatus for reducing track misregistration due to digital-to-analog converter quantization noise
US6456450B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 4, 1998 |
| Grant date | Sep 24, 2002 |
| Priority date | — |
| Expiry date | Dec 4, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05B2219/35536
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A method and apparatus for reducing track misregistration due to digital-to-analog converter quantization noise. In hard disk drive (HDD) servo control systems, quantization noises (or roundoff errors) due to the finite precision of the D/A converter (DAC) driving the VCM contribute a significant portion of the total track-misregistration (TMR). The present invention provides a quantization error feedback (QEF) technique to reduce TMR due to DAC quantization noises. The QEF technique according to the present invention offers a simple method of reshaping the spectrum of this noise to minimize its contribution to TMR. In the digital signal processor (DSP) implementation of the QEF schemes, the quantization error is monitored and accumulated in the DSP; when sufficient error has accumulated, the MSB feeding the DAC are modified such as to cancel the effect of the error. In addition, or alternatively, a state estimator may be driven with the most significant bits and a position error signal to reduce the power spectrum density function of the track misregistration at predetermined frequencies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.