Positioning system for data storage apparatus and record medium for use therewith
US4068269A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 29, 1976 |
| Grant date | Jan 10, 1978 |
| Priority date | — |
| Expiry date | Apr 29, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/5521
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A positioning system for data storage apparatus in which a magnetic transducer is positioned relative to data tracks on a moving record member by means of a closed loop servo system. Improved velocity control information is provided to the servo system by pre-recorded servo tracks read by a single servo head forming part of the closed loop system. Each servo track consists of a plurality of servo cells, alternate ones of which are laterally displaced by half a track width. A position reference signal is prerecorded in each cell at a point which is predetermined to permit the signal to be sensed by the single servo head independently of any other detectable signal. Accordingly, a position error signal derived from displaced cells is always 90.degree. out of phase with the position error signal derived from undisplaced cells. During a track access operation, when the servo head is moved from one track to another track, the displaced and undisplaced cells are sensed by the single servo head to provide two separate position error signals. Control circuits combine selected portions of the two position error signals to provide a composite signal of improved linearity from which the veloc…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.