| 摘要 |
PURPOSE:To shorten an analytic time by converting an acoustic waveform from analog to digital and storing the result in its time series, and then calculating time variation of an optional center frequency component by the Fourier integration of a load section in a digital area. CONSTITUTION:The sound in a body 1 to be tested is detected by a microphone 2 and amplified by a microphone amplifier 3. Then when an off-line analysis B is taken, a data recorder 4 is utilized, but when an on-line analysis A is taken, the output of the amplifier 3 is inputted to an A/D converter 5 directly. Acoustic data Xi obtained by the A/D conversion 5 is supplied to a digital frequency analyzer 6 to analyze its set center frequency component Xi, so that the result is plotted on a plotter 7. The plotter 7 calculates the linear approximate value in an analytic section set by a setter 9 by a method of the least squares, etc., to calculate the reverberation time, sound absorption rate, etc. |
