MIF-M consists of the flux-gate (BPP) and search-coil (DM2) sensors,analogue electronics boards with lowpass and highpass filters, filter bank with seven analogue passband filters, A/D converter and DC/DC converter.

The BPP flux-gate sensors of MIF-M instrument consists of the three identical flux-gate core rings, forming a right orthogonal system with fixed orientation with respect to the spacecraft body. They are mounted on the end of the boom 11 meters (BPP) apart from the spacecraft spin axis. Signals from the BPP components are divided in two frequency ranges 0-2 Hz and 2-25 Hz (DC and AC channels). These signals are transmitted to PRAM in digital form and in the analogue form directly to RTK spacecraft telemetry system. The signal from one of the components (selected by telecommand) is processed also by MIF-M filter bank.

The search-coil sensor of MIF-M (DM2) performs one component measurements of the AC magnetic field along the spacecraft Z axis in the broad frequency range. It is mounted on the boom together with its preamplifier. The analogue signal from the sensor is transmitted to the RTK telemetry system and processed by the filter bank in MIF-M.

The electronics block (inside MIF-M) contains an oscillator (frequency f = 12.5kHz), amplifier, demodulators and preliminary data processing unit.

PRAM is the digital waveform processor. It drives the A/D converters in MIF-M, accepts digital signal from MIF-M and processes it to fit the given bit rate. According to the mode of operation, the onboard algorithm performs selection between amplification ranges, averaging of DC field and filter data, creating the telemetry frames. Burst modes,switched on by the event selection algorithm, are possible with the buffer size equivalent to about four minutes of the prehistory information in the fastest mode.

The following algorithms are performed on board satellite:

• filter bank spectral analysis of the magnetic field and plasma current signal in MIF-M . Inputs of first two filters can be switched by the telecommand to any magnetic field component, measured by MIF-M flux-gate sensor. Inputs of the rest five filters can be switched between the signal from the search-coil sensor in MIF-M and the signal from the plasma current sensor in FGM-I,

• all analogue ASPI outputs are transmitted to RTK spacecraft telemetry system. Then they are digitized at a bit rate, determined by the telemetry operational mode. Real time transmission mode provides total bit rate of all ASPI analogue data equal to 16 kbit/s. Duration of the real time transmission is 2-3 hours each 2-4 days,

• digital telemetry frames created by PRAM are transmitted to SSNI telemetry system. These frames include DC and AC magnetic field waveforms and filter bank spectra measured by MIF-M. Analysis of the in-flight instrument operations have showed the high quality and reliability of the DC magnetic field measurements. MIF-M/PRAM DC magnetometer is working as the primary magnetic field experiment of the mission. AC magnetic field measurements are performed at high sensitivity in range 2-25 Hz, thus covering the gap usually existing in the frequency range between the DC and AC magnetic field experiments.