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:
Sep. 09, 2008
Filed:
Jul. 18, 2005
Roland Hoelzl, Munich, DE;
Michael Hermann, Villingen-Schwenningen, DE;
Roland Hoelzl, Munich, DE;
Michael Hermann, Villingen-Schwenningen, DE;
Prüftechnik Dieter Busch AG, Ismaning, DE;
Abstract
Method for nondestructive and contact-free detection of faults in a test specimen which is moved relative to a probe that detects a periodic electrical signal having a carrier oscillation whose amplitude and/or phase is/are modulated by any fault in the test specimen. The probe signal is filtered and sampled by a triggerable A/D converter stage to obtain a demodulated digital measurement signal which is filtered using a digital frequency-selective adjustable second filter unit to obtain a useful signal which is evaluated to detect a fault in the test specimen. The A/D converter stage is triggered at a fraction of the frequency of the carrier oscillation selected as a function of the fault frequency obtained as the quotient of the relative speed between the test specimen and the probe and the effective width of the probe, and the frequency-selective second filter unit is adjusted as a function of the fault frequency.