Abstract: An indirect calibration method for an electromagnetic induction method for determining physical parameters of an electrically conductive medium from a ratio (HS/HP) of a magnetic secondary field (HS), received in a receiving coil, to a magnetic primary field (HP) emitted from a transmitting coil electrically connected to a transmission signal generator, in which as measurement for the ratio (HS/HP) a received voltage (URx) is measured at an output of a receive amplifier electrically connected to the receiving coil, which is calibrated by series connection of at least one calibration coil and of a changeable calibration resistor and of a calibration factor (HCx/HP) which is adjustable therethrough, the receiving coil being permanently inductively coupled with the calibration coil, a calibration pulse, generated in the calibration coil, inducing a calibration field (HCx), inducing a magnetic flux in the receiving coil, areas and winding numbers of the receiving and calibration coils being known.

Abstract: An indirect calibration method for an electromagnetic induction method for determining physical parameters of an electrically conductive medium from a ratio (HS/HP) of a magnetic secondary field (HS), received in a receiving coil, to a magnetic primary field (HP) emitted from a transmitting coil electrically connected to a transmission signal generator, in which as measurement for the ratio (HS/HP) a received voltage (URx) is measured at an output of a receive amplifier electrically connected to the receiving coil, which is calibrated by series connection of at least one calibration coil and of a changeable calibration resistor and of a calibration factor (HCx/HP) which is adjustable therethrough, the receiving coil being permanently inductively coupled with the calibration coil, a calibration pulse, generated in the calibration coil, inducing a calibration field (HCx), inducing a magnetic flux in the receiving coil, areas and winding numbers of the receiving and calibration coils being known.