帯域信号の包絡線を使った音源寄与率の測定

概要

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This paper describes a method of estimating sound source contribution factors; it utilizes envelopes of band-passed signals picked up at the noise source and at the observation point. The coherence function has been used to express the contribution factor of a source signal to an observation point signal. In the open air, fluctuation of the transmission time caused by wind and/or air turbulence decreases the value of the coherence function; in other words the estimated transfer characteristics contain considerable error. The effect of such fluctuations increases in proportion to the length of transmission path and the frequency of signals. Thus, the authors propose in this paper the use of envelopes of band-passed signals instead of the original wave forms for estimating sound source contribution factors. With the cross spectral technique applied to those envelopes, the power transmission rate and the contribution factor of each frequency band can be obtained without being affected by a fluctuation of the transmission time. The method proposed here is useful for noise source detection.
社団法人日本音響学会の論文