| 摘要 |
PURPOSE:To obtain a compensation apparatus requiring no axial alignment of a compensation coil and a low sensitivity fluxmeter, by providing the low sensitivity fluxmeter, a high sensitivity magnetometer, a constant memory part, a compensation quantity calculation part, a subtraction circuit and a constant calculation part containing a high-band pass analogue filter and a high-band pass digital filter. CONSTITUTION:A compensation quantity calculation part 50 calculates the value of the noise magnetic field D represented by a predetermined formula from the outputs of low sensitivity magnetometers 11-13 and the output of a constant memory part 40. A subtraction circuit 60 subtracts the output of the calculation part 50 from that of a high sensitivity magnetometer 20 to output a compensated signal S. A constant calculation part 30 is constituted of a coefficient calculation part 31, a high-band pass analogue filter 32, a high-band pass digital filter 33 and a constant calculation part 34. The analogue filter 32 and the digital filter 33 are ones for realizing operators and the constant calculation part 30 can calculate a permanent magnetic field Hp, a 3X3 constant matrix A and a 3X3 constant matrix B at once according to a method of least squares. Therefore, compensation trimming (calculation of a constant) is easy and accurate compensation can be performed. |
