Measurement of frequency response functions in noisy environments

The geometric average is proposed as an alternative averaging technique for frequency response function measurements. It is shown that the geometric mean produces almost unbiased measurements, even if the input and output measurements are both disturbed by (normal distributed) noise. The proposed method is compared with the classical H/sub 1/ and H/sub 2/ measuring methods. As long as the signal-to-noise ratio is higher than 3 dB, the proposed method produces almost unbiased results in comparison with the other two methods.<>