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. 05, 1989
Filed:
Mar. 15, 1988
Bengt H Tornblom, Vaster.ang.s, SE;
Tornbloms Kvaliteskontroll AB, Vaster.ang.s, SE;
Abstract
A defect-sensing device for a test object, e.g. for detecting cracks in metal bodies with the aid of the eddy-current technique, has improved phase-selective properties by adding at least one product and/or quotient former to the signal processing equipment. The output signal from an ordinary phase-controlled rectifier can be substantially described via sin .alpha. and/or cos.alpha. functions in which indicates the phase position of the control signal in relation to the input signal. By multiplying sin.alpha. by cos .alpha. sin 2.alpha. cos 2.alpha. functions are obtained which in turn can be multiplied to obtain the function sin 4.alpha. corresponding to narrow sensitivity lobes in the transducer's impedance plane, thus permitting effective separation of the various types of vector signal resulting from detectable defects.