METHOD AND INSTRUMENT FOR MEASURING MAGNETIC PHYSICAL QUANTITY OF SAMPLE USING AC ELECTROMAGNETIC INDUCTION SYSTEM, METHOD AND INSTRUMENT FOR MEASURING WEIGHT, AND AC ELECTROMAGNETIC INDUCTION SENSOR

摘要

PURPOSE: To very quickly measure the magnetic physical quantity of a sample to be measured in a non-contacting state with higher accuracy than that of the conventional example. ;CONSTITUTION: By providing an AC electromagnetic induction sensor 1 composed of an external AC magnetic field impressing coil 5 and measuring coil 6 and moving a sample 7 to be measured along the direction of the magnetic field generated by the coil 5, the phase of an alternating current is changed so as to change the magnetic field and to induce an electromotive force in the measurement coil 6. Then, after a composite signal which is the sum of a signal induced by the external AC magnetic field and the signal of the magnetic physical quantity of the sample is measured as a signal to be measured, the measured signal of the net magnetic physical quantity of the sample is detected by removing the signal induced by the external magnetic field and the detected signal is digitized into a numerical signal as a basic measured signal. Finally, the magnetic physical quantity of the sample is calculated by multiplying the numerical signal by a magnetic physical quantity conversion factor.;COPYRIGHT: (C)1996,JPO