| 摘要 |
PURPOSE:To simply perform measurement with good accuracy, by calculating the square-law wave form of response obtained by adding an impulse sound to a sound field to be measured and calculating the average value of the square- law wave forms of response on and after the time when the response sufficiently attenuates. CONSTITUTION:The response converted to an electric signal by a microphone passes through a band-pass filter to remove the unnecessary frequency component thereof and is subsequently converted to a digital signal by an A/D converter. After the square-law wave form of the response is calculated in a digital signal processing part and the average value on and after the point of time when a reverberation wave form sufficiently attenuates. Subsequently, the DC component given by the average value of the square-law wave form is removed from said square-law wave form to calculate the integral value of the reverberation wave form and the logarithmic value thereof is outputted. At this time, the square-law wave form of the response is calculated by multiplying the same responses made difference in a measuring time and a reverberation time is calculated from the inclination of the reverberation wave form and the measurement of reverberation can be simply performed with good accuracy.
|
