通过理论分析激光语音检测系统, 提出一种引入参数估计误差的反正切解调补偿算法, 并建立了系统总谐波失真与关键参数及其误差的定量数学关系式。文中用总谐波失真(THD)和无杂散动态范围(SFDR)分别表征系统微振动信号解调效果和可以与大干扰信号(阻塞信号)相区别的最小信号值。实现了非接触、远距离、高灵敏度的微振动信号检测。通过实验和仿真均验证了反正切补偿算法的可行性。实验结果表明: 该系统可以检测音频范围内的微弱振动, 在现有光学硬件平台基础上, 利用文中提出的反正切补偿算法, 能在35 m范围内较好地还原语音信号。

The arctangent demodulation compensation algorithm with parameter estimation error was proposed through analyzing laser speech detection system in theory, then quantitative mathematical formulas between the total harmonic distortion(THD) and key parameters as well as errors were built up. The THD and spurious free dynamic range(SFDR) were considered in this paper, which indicated the demodulation effect of micro vibration signal and minimum signal value distinguished from a large disturbance signal (jamming signal), respectively. This system implemented non-contact, long distance and high sensitive acoustic micro vibration signal detection. Laboratory experiments and simulations were presented to verify the feasibility of the arctangent demodulation compensation algorithm. Results illustrate that this system can detect the micro vibration caused by sound wave and recover voice signal from received signal within 35 meters using the compensation algorithm based on optical hardware platform currently.