| 摘要 |
PROBLEM TO BE SOLVED: To provide an apparatus of measuring electrical resistance which can measure electrical resistance with a very high S/N ratio, even if it is a detecting voltage superimposed on noise. SOLUTION: The apparatus of measuring the electrical resistance includes a false random signal generator 3, in which a false random signal is impressed to electrodes 1a and 1b for applying a current, and the current flows to an iron pipe 10; an A/D converter 6, which inputs and digitizes an electric potential difference produced to the iron pipe 10 by the flow of this current through the electrodes 4a and 4b for electric potential difference detection; a signal component extractor 7a which extracts only the signal component among noise components and signal components, which are produced on the digitized detecting electric potential difference; a correlation operation section 7b, which computes the correlation value by performing the correlation operation between the same reference signal 7d as a pseudo-random signal and the signal component; and a resistive operation section 7c which seeks the electrical resistance of the iron tube 10, based on the voltage and the current of pseudo-random signal by setting the correlation value of the maximum to the electrical potential difference among the correlation values computed by the correlation operation section 7b to the voltage. COPYRIGHT: (C)2006,JPO&NCIPI
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