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:
Apr. 24, 2001
Filed:
May. 14, 1999
James Fitzpatrick, Sudbury, MA (US);
Christopher M. Carpenter, Sunnyvale, CA (US);
Quantum Corporation, Milpitas, CA (US);
Abstract
A synchronous calibration test circuit in accordance with the principles of this invention that uses a bandgap reference voltage of a PRML chip and a write clock synthesizer to generate an output reference calibration signal comprising a programmable frequency and whose amplitude is invariant with environmental conditions. This reference signal is injected at the input of a signal path of the PRML chip and measured after the PRML's A/D converter using the synchronous test calibration circuit of this invention. Since the programmable frequency reference signal is insensitive to voltage supply fluctuations as well as temperature and process variations this reference signal can be used to measure and characterize changes in the transfer function of the analog signal path of the PRML chip.