Abstract
An AC magnetic field of low frequency is applied to a measurement object and distribution of induced current is measured to detect distribution of the impedance characteristic of the measurement object. A magnetic impedance measuring device includes: an application coil for generating an AC magnetic field whose frequency can be varied and a power source for the application coil; at least a pair of magnetic sensor means formed by two magnetic sensors for detecting a vector component parallel to the application coil surface by a vector component orthogonal to the magnetic field generated by the measurement object; magnetic sensor measuring means arranged apart from the application coil surface to oppose to the measurement object for measuring a detection signal of the magnetic sensor means; a lock-in amplifier circuit for detecting a signal of the same frequency as the application coil from the output of the magnetic sensor measuring means; and analysis means for analyzing the output intensity and the phase change of the magnetic sensor by the output signal of the lock-in amplifier circuit.
| Original language | English |
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| Patent number | WO2006109382 |
| IPC | G01R 33/ 02 A I |
| Priority date | 3/14/05 |
| Publication status | Published - Oct 19 2006 |