The article describes a device designed to measure the shielding coefficient of a magnetic field in the near zone and its dependence on the frequency of changes in the magnetic field. The screening coefficient is measured taking into account the nonlinearity of the characteristics of the material from which the magnetic screen is made. The test action generation module sets the current flowing through the coil containing a superposition of DC and AC signals. The presence of a constant component in the test exposure makes it possible to compensate for an external constant or slowly changing magnetic field and thereby reduce the error in determining the shielding coefficient. The results of measuring the frequency dependence of the magnetic field shielding coefficient in the near zone, as well as the main characteristics of the created device are presented.

Keywords: screening coefficient, nonlinear magnetometer, screening coefficient meter, magnetometry, digital attenuator, hall magnetometer, magnetic field compensation