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:
Sep. 18, 2001
Filed:
Feb. 16, 2000
Yoichi Ogura, Ehime, JP;
Shoji Marukawa, Ehime, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
When a playback signal of recorded data which is a DC free code has non-linearity, the playback signal is equalized by a waveform equalization unit, and sampled by an analog-to-digital converter. The sample data is binarized, and an offset amount is detected by utilizing the feature of the DC free code, and then the reference level of the analog-to-digital converter is controlled so that the output of a first integrator becomes 0. Thereafter, the output of a level shift circuit is input to a second integrator, and the level shift amount is controlled so that the output becomes 0. The converged value is retained. After this learning, by using the retained level shift amount, the reference level is controlled so that the output of the second integrator becomes 0, thereby performing speedy and accurate DC offset control.