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.

Date of Patent:
Jun. 25, 2013

Filed:

Sep. 18, 2009
Applicants:

Kazuhiro Yamamoto, Tokyo, JP;

Toshiyuki Okayasu, Tokyo, JP;

Inventors:

Kazuhiro Yamamoto, Tokyo, JP;

Toshiyuki Okayasu, Tokyo, JP;

Assignee:
Attorney:
Assistant Examiner:
Int. Cl.
CPC ...
G01R 31/00 (2006.01);
U.S. Cl.
CPC ...
Abstract

A first transform unit transforms clock change point information which indicates the change timing of a clock signal into information with respect to the frequency domain thereof so as to generate first clock change point frequency information. A digital filter performs filtering of the first clock change point frequency information so as to generate second clock change point frequency information. A second transform unit inverse-transforms the second clock change point frequency information into information with respect to the time domain so as to generate second clock change point information. A judgment unit evaluates a DUT based upon difference data between the change timing represented by the data change point information and the change timing represented by the second clock change point information in increments of phases.


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