Shams Qamar A, Soto Hector L, Zuckerwar Allan J
NASA Langley Research Center, Hampton, VA 23681, USA.
J Acoust Soc Am. 2009 Sep;126(3):1107-10. doi: 10.1121/1.3167483.
Crosstalk in electrostatic actuator calibrations is defined as the ratio of the microphone response to the actuator excitation voltage at a given frequency with the actuator polarization voltage turned off to the response, at the excitation frequency, with the polarization voltage turned on. It consequently contributes to the uncertainty of electrostatic actuator calibrations. Two sources of crosstalk are analyzed: the first attributed to the stray capacitance between the actuator electrode and the microphone backplate, and the second to the ground resistance appearing as a common element in the actuator excitation and microphone input loops. Measurements conducted on 1/4, 1/2, and 1 in. air condenser microphones reveal that the crosstalk has no frequency dependence up to the membrane resonance frequency and that the level of crosstalk lies at about -60 dB for all three microphones-conclusions that are consistent with theory. The measurements support the stray capacitance model. The contribution of crosstalk to the measurement standard uncertainty of an electrostatic actuator calibration is therewith 0.01 dB.
静电致动器校准中的串扰定义为在给定频率下，致动器极化电压关闭时麦克风响应与致动器激励电压之比，与极化电压开启时在激励频率下的响应之比。因此，它会导致静电致动器校准的不确定性。分析了串扰的两个来源：第一个归因于致动器电极与麦克风背板之间的杂散电容，第二个归因于在致动器激励和麦克风输入回路中作为公共元件出现的接地电阻。对1/4英寸、1/2英寸和1英寸空气电容式麦克风进行的测量表明，在膜共振频率之前，串扰与频率无关，并且对于所有三个麦克风，串扰水平约为-60 dB，这一结论与理论一致。这些测量结果支持杂散电容模型。串扰对静电致动器校准测量标准不确定度的贡献因此为0.01 dB。
