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. 21, 1987
Filed:
Feb. 04, 1985
Dale B Chapman, San Jose, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A phase discriminator and data standardizer apparatus measures phase difference between a data signal obtained from a magnetic disk device and a variable-frequency reference data clock. From the measured phase difference, the apparatus develops a phase difference signal used to adjust the frequency of the reference data clock in order to reduce the phase difference. The apparatus includes a multi-state latch circuit that responds to the input data and clock signals by measuring the phase in a phase measurement transition cycle in which only one state variable changes at a time and producing the phase difference signal based upon the measurement. A gate responds to the measurement transition cycle by producing the phase difference signal. The apparatus further standardizes the input data so as to provide the data in a format that is predictably standardized in its time relationship to the reference data clock signal.