Kathleen Anne Connelly

US Patent:

49146459, Apr 3, 1990

Filed:

Jan 25, 1988

Appl. No.:

7/147690

Inventors:

Kurt W. Getreuer - Colorado Springs CO
Johannes J. Verboom - Bergeyh, NL
David L. Schell - Colorado Springs CO
David E. Lewis - Colorado Springs CO
Gregory V. Hofer - Colorado Springs CO
Kathleen M. Connelly - Colorado Springs CO
James C. McDonald - Colorado Springs CO
Pierre R. Sonneville - Weert, NL
Cees van Nimwegen - Eindhoven, NL

Assignee:

Laser Magnetic Storage International Company - Colorado Springs CO

International Classification:

G11B 709

US Classification:

369 44

Abstract:

An optical disk recording system including a record medium is disclosed for providing an accurate track crossing count and an accurate track following signal. A first embodiment utilizes off-centered wobbled areas located in the headers of the record medium. The high frequency content of a first signal is combined with the low frequency content of a second signal, which is generated using the wobbled areas. In another embodiment, light-reflective discontinuities are provided in the header areas of the record medium. A qualifier and an AGC are utilized in providing a corrected track following signal. In still another embodiment, reflective discontinuities are located in the servo areas of the record medium. In such an embodiment, it is preferred that there is a fixed gain adjustment to a radial push-pull signal. With regard to each of the three aforesaid embodiments, a track following signal is corrected to compensate for aberrations that are caused by a shift of the light beam returned from the record medium surface.