高声压、宽频带电容传声器分析和设计

为了满足声学测试提出的技术指标,即设计出频响范围更宽、动态范围更大的1/4 in电容传声器。采用电容传声器的集中参数模型,根据工作原理导出其输出电压变化与电容两板极间距离变化成正比的公式和灵敏度计算公式,而后又通过所导出的电容传声器传输函数分析了频响特性。通过对灵敏度和动态范围的计算以及对动态范围的估计,最终设计出开路灵敏度为1.9 m V/Pa、频响范围为2 Hz~79 k Hz、最高声压级不低于160 d B的电容传声器,该性能满足该系列传声器频响范围5 Hz~70 k Hz、最高声压(有效值)不低于160 d B的电容传声器的性能指标。上述结果表明设计方法可行,并提出了进一步改进此传声器性能的几点考虑。

Analysis and design of a wideband high sound pressure condenser microphone

In order to meet the technology indicators of acoustic testing, namely to design a 1/4 inch condenser microphone with wider frequency range and wider dynamic range, the lumped parameter model of the condenser microphone is adopted, and the formula of the output voltage variation proportional to the variation of the distance between two plates of capacitor is derived based on the system principle as well as the sensitivity formula. Furthermore, the characteristics of frequency response are analyzed with the derived transmission function of the condenser micro-phone. Through the calculations of sensitivity and dynamic range and the estimation of dynamic range, the condenser microphone with an open circuit sensitivity of 1.9 mV/Pa, a frequency response range of 2 Hz~79 kHz and the highest sound level not less than 160 dB is developed, the performance of which meets the index requirements for the series of microphones, i.e. a frequency response range of 5 Hz~70 kHz and the highest sound pressure (RMS) not less than 160 dB. The above-mentioned results show the feasibility of the design. In addition, some consideration to further improve the performance of the microphone is proposed.