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:
Aug. 17, 1982
Filed:
Sep. 04, 1980
John H Blagaila, Boulder, CO (US);
James F Hopper, Louisville, CO (US);
Storage Technology Corporation, Louisville, CO (US);
Abstract
An address mark detection circuit for use in a magnetic disk data storage unit is disclosed which features a Mealy sequential machine for providing a sequence of logical steps for the testing of sampled data in the search for an address mark; comparison between a given address mark and sampled data is eliminated. In a preferred embodiment, the specific mark to be detected is a first high frequency field followed by a second lower frequency field. The data is repeatedly sampled, and a digital frequency detector is used to provide a two bit signal to the sequential machine for stepping it in a direction corresponding to the frequency of the sample. The circuit allows elimination of means for detection of rotational position sensing information from a dedicated disk surface and elaborate phase-locked-loop circuitry for generating a data rate clocking signal in favor of simple and reliable logic circuitry.