Digital servo demodulation for sampled amplitude magnetic recording
US5854714A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 1996 |
| Grant date | Dec 29, 1998 |
| Priority date | — |
| Expiry date | Oct 29, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/10055
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A discrete time servo demodulation technique incorporated within a sampled amplitude read channel to demodulate embedded servo field information stored on a magnetic medium. The servo field information is transduced by a read head into an analog signal, and converted to a sequence of sample values in the read channel. The demodulation technique is responsive to the sample values and includes a discrete time peak detector for detecting servo data, and a discrete time servo burst amplitude detector for measuring the amplitude of servo bursts. Peaks are detected in the analog read signal by sensing a change of slope from the sequence of sample values. The peaks are qualified by polarity in that a peak is detected only if its polarity is opposite in sign from the previous peak. The servo burst amplitudes are measured by interpolating, rectifying, and accumulating the sequence of sample values corresponding to the servo bursts. A plurality of registers store the amplitude measurement of corresponding servo bursts such as the four servo bursts in a quadrature system. The sample values are interpolated, squared, and the sampling frequency dithered in order to decrease the sensitivity of t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.