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:
May. 15, 2001
Filed:
Dec. 30, 1998
Ryohei Kuki, Tokyo, JP;
Koshiro Saeki, Irvine, CA (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
This invention relates to improvements in servo Gray code detection techniques in rotating data storage drives such as hard disk drives, or the like. The detection technique uses a rate ¼ Gray code servo signals equalized to a PR4 target, and a matched filter detector, and can realize a servo Gray code detector having high speed and performance. The Gray code detector (,) has an input (,) for receiving an input signal containing a Gray code that has been equalized to a PR4 target and a circuit (,) for processing said input signal to determine a maximum Euclidean distance from zero to a value of the Gray code. The construction of the detector (,) depends upon the particular Gray code that is employed. A threshold detector (,) determines whether the determined Euclidean distance exceeds a predetermined threshold, and produces a first output signal if the Euclidean distance exceeds the predetermined threshold and to produce a second output signal if the Euclidean distance does not exceed the predetermined threshold. An exclusive-or gate (,) may also be provided if the Gray code results in negative output numbers to compare an output of said comparator to an alternating sequence of zero and one.