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:
Oct. 08, 1991
Filed:
Apr. 07, 1989
Kiyoshi Tateishi, Tokorozawa, JP;
Haruyasu Sakata, Tokorozawa, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A tracking servo system for use in a disc player having a pickup, for playing an information recording disc having a recording track, the tracking servo system comprises an equalizing circuit for compensating for the frequency characteristic of the tracking error signal for the tracking servo operation, the equalizing circuit means performing a compensating operation in accordance with a predetermined compensation characteristic during a normal playback of the recording disc. The system is provided with a control device for varying coefficients determining the compensation characteristic of the equalizing circuit so that the compensation characteristic has a phase margin in a middle frequency range larger than a corresponding phase margin in the predetermined compensation characteristic upon closure of the tracking servo loop, and a middle frequency gain of the equalizing circuit means is gradually increased with time until the compensation characteristic equals the predetermined compensation characteristic when a predetermined time period elapses.