论文部分内容阅读
光纤布拉格光栅(FBG)用于微弱振动检测时,当被测振动太微弱时系统输出传感信号的信噪比小于1,从时域采集的数据很难直接测得到信号的幅度和频率信息。提出一种信号处理方法,即将传感器在时域测量获得的连续数据分段后,对每段数据分别进行快速傅里叶变换获得其对应的功率谱信号,然后将频域信号做叠加平均得到新的数据。实验结果表明,采用这种频域叠加平均的方法处理后,FBG传感信号在频域内的信噪比提高了15.6dB,明显提升了微弱信号的检测能力。初步实验表明:该系统对FBG波长变化的检测灵敏度可提高到1.5fm。该信号处理方法特别适合噪声环境恶劣、被测信号以一定频率持续存在的工程应用领域,对实际环境下微小振动的识别与检测具有较大的意义。
Fiber Bragg Grating (FBG) is used for weak vibration detection. When the measured vibration is too weak, the signal-to-noise ratio of the system output sensing signal is less than 1. It is hard to directly measure the signal amplitude and frequency information from the time-domain data. A signal processing method is proposed. After segmenting the continuous data obtained by the sensor in the time domain measurement, fast Fourier transform is performed on each piece of data to obtain the corresponding power spectrum signal, and then the frequency domain signals are superimposed and averaged to obtain new signal The data. The experimental results show that the signal-to-noise ratio of FBG sensing signal increases by 15.6dB in the frequency domain after using this method of frequency-domain superposition and averaging, which obviously improves the detection ability of weak signal. Preliminary experiments show that: the detection sensitivity of the system to FBG wavelength change can be increased to 1.5fm. The signal processing method is especially suitable for engineering applications where the noise environment is harsh and the measured signal persists at a certain frequency, which is of great significance to the identification and detection of tiny vibrations in an actual environment.