In this paper, we introduce a novel approach for effectively reducing nonlinear distortion in single back-plate condenser microphones, i.e., most MEMS microphones, studio recording condenser microphones, and laboratory measurement microphones. This simple post-processing technique can be easily integrated on an external hardware such as an analog circuit, microcontroller, audio codec, DSP unit, or within the ASIC chip in a case of MEMS microphones. It significantly reduces microphone distortion across its frequency and dynamic range. It relies on a single parameter, which can be derived from either the microphone's physical parameters or a straightforward measurement presented in this paper. An optimal estimate of this parameter achieves the best distortion reduction, whereas overestimating it never increases distortion beyond the original level. The technique was tested on a MEMS microphone. Our findings indicate that for harmonic excitation the proposed technique reduces the second harmonic by approximately 40 dB, leading to a significant reduction in the Total Harmonic Distortion (THD). The efficiency of the distortion reduction technique for more complex signals is demonstrated through two-tone and multitone experiments, where second-order intermodulation products are reduced by at least 20 dB.

翻译：本文提出一种新颖方法，可有效降低单背板电容麦克风（包括大多数MEMS麦克风、录音棚电容麦克风及实验室测量麦克风）的非线性失真。该后处理技术可便捷地集成于外部硬件，如模拟电路、微控制器、音频编解码器、DSP单元，或在MEMS麦克风场景中集成于ASIC芯片内部。该方法能显著降低麦克风在全频段与动态范围内的失真，其核心仅依赖单一参数——该参数既可从麦克风物理参数推导获得，也可通过本文提出的简易测量方法获取。对此参数进行最优估计可实现最佳失真抑制效果，而高估该参数值亦不会使失真水平超过原始状态。我们在MEMS麦克风上对该技术进行了验证。研究结果表明：在谐波激励下，该技术可将二次谐波降低约40 dB，从而显著降低总谐波失真（THD）。通过双音与多音实验进一步验证了该失真抑制技术对复杂信号的有效性，其中二阶互调产物可降低至少20 dB。