| 摘要 |
The displacement of an object of an electrically conducting material is determined. To determine the displacement, an electromagnetic field creating eddy currents in the object is established by means of a transducer being placed adjacent to and spaced from the object, and a first electrical signal which represents the impedance of the transducer is provided. The first electrical signal may be represented by a first vector having first and second components, the first component being a second vector dependent on characteristics of the transducer and on the distance between the transducer and the object, and the second component being a product of a first factor which is a real number and a second factor which is a third vector. Here, the first factor depends on the characteristics of the transducer, the distance between the transducer and the object, and characteristics of the object, and the third vector depends substantially on the characteristics of the transducer. The first electrical signal is processed, which processing includes stimulating projection of the first vector onto an axis being generally at right angles to the second component so as to substantially eliminate the dependency on the characteristics of the object. The invention also relates to a unit for linearization of an electrical signal. An input signal is approximated to a polynomial function with positive broken exponents. The polynomial function is used in a feed back loop.
|
