System for position detection on a rotating disk
US4587579A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 30, 1982 |
| Grant date | May 6, 1986 |
| Priority date | — |
| Expiry date | Dec 30, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/59677
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An information reading/writing head is positioned to follow data tracks that are formed concentrically on a magnetic recording disk. A set of spiral radial position-indicating markings if formed which can be detected on the disk optically, or capacitively. The position of the head is determined by sensing the spiral markings. The reference for the phase detection is detected by sensing radial indicia on the disk periphery or spiral markings of servo data with a different pitch and frequency from the position-indicating spiral markings. A servo control system operated by the above disk, reads the radial position-indicating spiral pattern and the reference pattern on the disk and compares the relative phases of the two to compute the track position of the head. A set of phase-locked loops with subsequent phase comparators is used to decode the servo data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.