Pulse discharge sound source and its application to acoustic measurement
Hideo Shibayama, Ken’iti Kido · The Journal of the Acoustical Society of America · 1988
This paper describes a pulse discharge sound source without any diaphragm, and its application for acoustic measurements. The waveform of the sound pulses radiated from this source is simple and reproducible. The power spectra of these pulses have no zero points up to 90 kHz. The duration of the sound pulse is about 50 uμs, and is dependent on the gap length between the discharge electrodes. The directivity function of the sound source is the same as that of a line source that is equal to the gap length. The sound generating spot is small, and the sound source requires no baffle board. As a result, no reflection from the sound source itself is produced. The timing of sound generation is stable and controllable. As examples of acoustic measurements utilizing the sound source, the estimated results of acoustic impedance characteristics of materials and their frequency responses of diffraction are shown. The estimated results agreed well with the calculated ones. A measuring system can be considerably simplified by use of the pulse discharge sound source and the digital signal processing technique. Measuring time can also be reduced.