Multiple frequency digital eddy current inspection system
AssigneeThe United States of America as represented by the Secretary of the Air Force
InventorsJohn H. Flora, Henry T. Gruber
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Abstract
An apparatus for inspecting for cracks under installed fasteners and the like using a multiple frequency digital eddy current system. A computer with a plurality of digital arrays generate drive signals which are converted to analog and applied to the test coil, a second set of digital arrays generate balance signals, are adjusted in amplitude and phase and drive signals so that the output of the test coil is zero in a test specimen, output signals from a work piece are processed in the computer giving phase-sensitive crack detection.
Claims8
A multiple frequency digital eddy current inspection system for use in non destructive testing comprising:
- an eddy current test coil;
- a computer having a plurality of digital signal generating arrays for sequentially generating said multiple frequencies;
- means for changing digital signals to analog signals connected between the computer and the test coil;
- amplifier means for receiving eddy current signals from the test coil filter means connected to the amplifier means for selecting a desired signal;
- means having an input connected to the filter means for changing the filtered signal from an analog signal to a digital signal and an output connected to the computer for providing results of the eddy current inspection.
Dependencies are inferred from the claim text.