The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 17, 1990
Filed:
Oct. 31, 1988
Gregory V Hofer, Colorado Springs, CO (US);
James C McDonald, Black Forest, CO (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A method for operating a programmable digital signal processor in an optical disk drive to compensate tracking and/or focus servo system gain each time a new disk is inserted. The digital signal processor receives a servo error signal and outputs a servo control signal. Data characteristic of a desired servo system gain at a predetermined test frequency is stored in memory. The digital signal processor generates a test signal at the test frequency and sums the test signal with the servo error signal. Servo system gain at the test frequency is determined by computing the ratio of the amplitude of the servo error signal before it is summed with the test signal and the amplitude of the summed servo error signal and test signal. A corrected gain factor is computed as a function of the current servo system gain, the desired servo system gain and current gain factor. The corrected gain factor is stored in memory. The servo error signal is thereafter multiplied by the gain factor so servo system gain equals the desired servo system gain.