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US 5,854,553 AGranted
Digitally linearizing eddy current probe
AssigneeSKF Condition Monitoring, Inc.
InventorsJohn T. Barclay, Phillip L. Maness, Leroy R. Bannach
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Abstract
The output of an eddy current probe is demodulated and subsequently linearized using an analog to digital converter, a digital signal processor, and a memory. The linearized digital output signal is converted back to an analog signal, the voltage of which is preferably directly proportional to the position of the conductive target in relation to the probe.
Claims20
An apparatus for determining the position of a conductive target, comprising:
- an eddy current probe, wherein said eddy current probe comprises an inductor mounted near said conductive target;
- an oscillator connected to said inductor;
- a demodulator having an output comprising the peak voltage across said inductor wherein said peak voltage has a first functional dependence on the position of said conductive target;
- an analog to digital converter digitizing said demodulator output to produce a first set of digital data;
- a signal processor performing arithmetic operations on said first set of digital data to produce a second set of digital data;
- and
- a digital to analog converter having as an input said second set of digital data and as an output an analog signal which has a second functional dependence on the position of said conductive target, wherein said second functional dependence is substantially linear.
4 more elements
Dependencies are inferred from the claim text.