Method and device for analysing a magnetic material, and analyser including the device
AssigneeMagnisense Technology Limited
InventorLuc Lenglet
Life of this patent
Estimating the term…
Abstract
Disclosed is a method of analysing a magnetic material which includes the construction of a signature S(H) of the magnetic material formed from at least two points S(H)P, this construction including obtaining the value of each point S(H)P by measuring, over each period fraction, the amplitude and possibly the phase of a harmonic of the magnetic field induced in the magnetic material, said amplitude and phase being obtained in response only to an excitation during this period fraction, the harmonic having a frequency nfH, where n is a non-zero positive integer; and the identification and/or the determination of the mass of the magnetic material from several points of the constructed signature S(H).
Claims19
A method of analysing a magnetic material comprising:
- a) excitation of the magnetic material simultaneously with:
- a low-frequency excitation magnetic field (HL) of periods TL, the period TL comprising at least first and second period fractions such that the average of the instantaneous value of the low-frequency magnetic field over the first period fraction is different from the average of its instantaneous value over the second period fraction, each period fraction having a duration of at least 100 nanoseconds and
- a high-frequency excitation magnetic field (HH), the variation of the instantaneous value of which over the course of time is periodic with a frequency fH, the frequency fH of the high-frequency excitation magnetic field being at least twice the frequency fL of the low-frequency magnetic field;
- b) the construction of a signature S(H) of the magnetic material formed from at least two points S(H)P, this construction including obtaining the value of each point S(H)P by measuring, over each period fraction, the amplitude and possibly the phase of a harmonic of the magnetic field induced in the magnetic material, said amplitude and phase being obtained in response to the excitation during this period fraction, the harmonic having a frequency nfH, where n is a non-zero positive integer;
- and
- c) the identification and/or the determination of the mass of the magnetic material from several points of the constructed signature S(H).
A device for analysing a magnetic material, comprising:
- a) a generator designed to excite the magnetic material simultaneously with:
- a low-frequency excitation magnetic field (HL) of periods TL, the period TL comprising at least first and second period fractions such that the average of the instantaneous value of the low-frequency magnetic field over the first period fraction is different from the average of its instantaneous value over the second period fraction, each period fraction having a duration of at least 100 nanoseconds and
- a high-frequency excitation magnetic field (HH), the variation of its instantaneous value of which over the course of time is periodic with a frequency fH, the frequency fH of the high-frequency excitation magnetic field being at least two times the frequency fL of the low-frequency magnetic field;
- b) a signature constructor for constructing a signature S(H) of the magnetic material formed from at least two points S(H)P, this constructor being capable of obtaining the value of each point S(H)P by measuring, over each period fraction, the amplitude and possibly the phase of a harmonic of the magnetic field induced in the magnetic material, said amplitude and phase being obtained in response only to the excitation during this period fraction, the harmonic having a frequency nfH, where n is a non-zero positive integer;
- and
- c) a module for identifying and/or determining the mass of the magnetic material on the basis of several of the points of the constructed signature S(H).
Dependencies are inferred from the claim text.