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. 18, 1999
Filed:
Mar. 15, 1997
Kenneth R Wilsher, Palo Alto, CA (US);
Suresh N Rajan, San Jose, CA (US);
William K Lo, San Jose, CA (US);
Schlumberger Technologies, Inc., San Jose, CA (US);
Abstract
A probe beam is used to sample the waveform on an IC device under test (DUT) during each cycle of a test pattern applied to the DUT. A reference laser beam is also used to sample the DUT. For each cycle of the test pattern, the reference and probe beams sample the DUT at the same physical location, but at displaced times with respect to each other. Each reference measurement is made at a fixed time relative to the test pattern while the probe measurements are scanned through the test-pattern time portion of interest, in the manner normal to equivalent time sampling, to reconstruct the waveform. For each test cycle, the ratio of these two measurements is taken. The fluctuations of these ratios due to noise is greatly reduced as compared to fluctuations of the probe measurements taken alone. Thus, a smaller number of averages is required to reconstruct the waveform.