| 摘要 |
The method includes the steps of sampling the electric signal by device of a sample-and-hold circuit (1) at a predetermined sampling frequency (fA), and converting it in an A/D converter (2) into digital values (f(ntA)). Squared digital values (f<2>(ntA)) are formed from the digital values in a squaring stage (3), which are subsequently digitally filtered in a calculation unit with a non-recursive digital filter (FIR) formed as a low-pass filter (25), and a square root stage (30), to form the measurement signal (S). The squared digital values are filtered before their supply to the calculation unit, at least once in a pre-filter arrangement (5,15) formed as a low-pass filter, and are subsequently subjected to a sampling rate reduction (10,20).
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