光学法测量驻波管中声压量值的优化研究

Optimization of Sound Pressure Measurement in Standing Wave Tube by Optical Method

针对目前光学法测量空气声声压与实验室标准传声器之间存在一定偏差的问题,以驻波管中的声场为测量对象,利用双光束激光多普勒测量系统,以檀香燃烟作为示踪粒子,测量光学干涉位置处的声压量值。优化了基于商用光子相关器的直接自相关算法,通过时域加窗的光子自相关方法,有效消除粒子自身热运动产生的影响。实验结果表明,时域加窗光子相关光谱法解调结果与实验室标准传声器测量结果的偏差小于0.11dB。

To decrease the deviation between the airborne sound pressure measured by the optical method and laboratory standard microphone,an optimization of the optical method was carried out in a standing wave tube. The dual-beam Laser Doppler measurement system was used to measure sound pressure at the position of optical interference,with sandalwood smoke as the tracer particle. The autocorrelation algorithm based on the commercial photon correlator is optimized,and the influence of the thermal motion of the particles in the sound field is effectively eliminated by the gated photon autocorrelation method. The experimental results showed that the deviation between the demodulation results of gated photon correlation spectroscopy and the results of laboratory standard microphone is less than 0. 11 dB.