Numerical Study on the Phase Sensitivity Variation in Low Frequency Primary Microphone Calibrations

Applied Sciences

Aibing Liu¹  Xianyue Gang¹  Lijun Li¹  Fan Zhang¹  Di Liu¹ 

[1] School of Transportation and Vehicle Engineering, Shandong University of Technology, 1 Xincunxi road, Zibo 255000, Shandong, China;

关键词: phase;    sensitivity;    microphone;    primary calibration;    multi-physics;   

DOI  :  10.3390/app10113799

来源: DOAJ

【 摘 要 】

The low frequency phase characteristics of microphones in a monitoring system are crucial for characterizing large-scale natural and artificial activities—e.g., earthquakes, nuclear explosions, or rocket launchings. At present, microphones are simultaneously calibrated using in-situ or calibrator methods to get their phase consistency. However, the essential primary calibration, which traces their phase sensitivity to basic physical quantities, is grossly overlooked. Recently, we speculated that the microphone phase sensitivity is acoustically controlled by the pressure leakage and heat conduction effects in its back chamber, which will vary at low frequencies. Therefore, by means of the FEA (Finite Element Analysis) technique, simulations of laser pistonphone-based primary microphone calibrations are conducted both in the frequency and time domains. The frequency domain simulation quantifies the phase variation, while the time domain analysis helps us to understand the variation mechanism. It is found that the low frequency phase sensitivity is greatly influenced by its geometries and the venting state and should be pre-calibrated before serving.

【 授权许可】

Unknown