Micromagnetic hardness testing
To determine the hardness, the material to be measured is exposed to an alternating magnetic field and the reorientation of the individual magnetic domains in the microstructure of the material is measured. The time-amplitude signal recorded by the micromagnetic sensor is digitized by the QASS µmagnetic measuring system and processed by a Fast Fourier Transformation (FFT) in real time to reveal the frequency components (pitches) hidden in the signal. The method used by QASS for spectral analysis is called High Frequency Pulse Measurement (HFIM). Within the scope of the spectral analysis, machine noise and interference noise can be specifically filtered out of the signal data by means of a spectral filter (also called frequency mask). This improves the relationship between useful and interfering signals.