LS2F传声器的高频自由场互易校准

Free Field Reciprocity Calibration of LS2F Microphone in High Frequency

为满足空气超声声压量值的溯源需求，利用PULSE分析仪和互易校准仪，采用时间加窗技术对频域信号转换得到的时域信号进行处理，建立了LS2F传声器的高频互易校准装置，实现了实验室标准传声器的20—51kHz的自由场灵敏度校准。通过对比时间加窗处理前后的实验数据，分析了驻波和墙体发射波对传声器灵敏度的影响。结果表明，高于40kHz时，时间加窗处理技术能够减小1．0dB的偏差。

To meet the requirements for measurement traceability of air borne uhrasound pressure, PULSE analyzer and reciprocity calibration apparatus are used to found the free-field reciprocity calibration system. High frequency free field sensitivity of LS2F microphones and frequency response from 20 kHz to 51 kHz are obtained with time selective technology. The data with and without time selective technology are compared and the influences of standing wave and reflected wave from wall are analyzed . The result shows that standard deviation is reduced by 1.0 dB with this technology above 40 kFlz.