Isotropic measurement of electric and magnetic ELF fields. Frequency-selective FFT measuring system with high dynamic range for electric and magnetic fields from 1 Hz to 400 kHz. Sensors in the three spatial directions provide isotropic results for selective and broadband measurements. Uses the Weighted Peak method for standard measurement of complex signals. This method, patented by Narda, evaluates the signal by means of mathematical convolution in the time domain. The result is a direct display of exposure as a percentage of the limit value. This makes the application particularly fast and easy to use. Weighted Peak is the basis of the limit value curves of the most important standards.