为实现微弱振动信号的实时、高精度解调,提出一种基于现场可编程逻辑门阵列（FPGA）的激光多普勒微弱振动检测及信号处理方法。采用全光纤结构的光学系统,振动信号处理系统则以FPGA为核心设计。改进相位解缠模块,在增大振动测量范围的同时,使其能适用于简谐振动与复杂振动。通过模拟振动实验验证了改进后相位解缠模块,且当振幅在80 μm以内时,测量精度在5‰以内。通过对压电陶瓷实际振动目标测振实验,其频率测量误差在1 Hz以内,振幅与频率的测量精度均在1%以内。实验验证了该振动信号处理方案对于扩大振动测量范围与实现高精度目标振动解调的有效性。

In order to realize the real-time and high-precision demodulation of microvibration signal, a method of laser Doppler microvibration detection and signal processing based on FPGA is proposed. The optical system with all-fiber structure was adopted, and the vibration signal processing system was designed with FPGA as the core. The phase unwrapping module was improved to enlarge the measuring range of vibration and make it suitable for simple harmonic vibration and complex vibration. The improved phase unwrapping module was verified by simulated vibration experiments. When the amplitude was less than 80 μm, the measurement accuracy was less than 5‰. Through the vibration measurement experiment of the actual vibration target of piezoelectric ceramics, the frequency measurement error was less than 1 Hz, and the measurement accuracy of amplitude and frequency was less than 1%. The experimental results show that the vibration signal processing scheme is effective in expanding the vibration measurement range and realizing high-precision target vibration demodulation.