抄録
New method of measuring reverberation decay curves was proposed, aiming to apply the curves which are used in the acoustics, to the analysis of transient characteristics of dumped systems.
This method was derived using the Wigner distribution applied to a noise model of measuring reverberation.
The reverberation decay curves for computer generated impulse responses are calculated by the Schroeder, Fourier transform and proposed method. And a comparative study was made.
The proposed method are shown to contain the following desirable properties:
1) Calculated decay curves are free from the band pass filter characteristics.
2) Processing time is equivalent to one of the Fourier method. Especially, to analyze up to the half of the Nyquist frequency, the proposed method gives double resolution with equivalent processing time, or needs half of processing time with equivalent resolution, comparing to the Fourier method.
3) Spectral leakage along the frequency direction is extremely less. Therefore higher discrimination of some resonant components is attained.
4) Desirable decaying figure are calculated, even though the narrow band pass filter is considered.
5) Even if the passed band contains no resonant components, the reverberation curves presents the desirable initial decay, and the rest of the part remains in the lower level.
6) Effect of the finite integral in terms of time is less. The desirable decay figure are given in the wide range of time.
7) The reverberation decay curves are not always monotonous decrease. Temporary exchange of energy with sidebands makes the curves uneven.
