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FBG传感系统中,噪声的存在严重影响了解调系统中心波长检测的精确度。小波变换具有强大的时频分析能力,利用平稳小波变换对FBG反射谱信号进行了去噪处理,并与普通离散小波变换的去噪效果进行了对比。结果表明:对于实际FBG反射谱,该方法信噪比要比普通离散小波变换高出3 dB,而均方差仅为普通离散小波变换的1/4。而且该方法保证了消噪后FBG反射谱信号峰值即对应中心波长,克服了普通离散小波变换因下采样操作而造成的非线性相位和非平移不变的缺点。
FBG sensing system, the presence of noise seriously affects the demodulation system center wavelength detection accuracy. Wavelet transform has a strong ability of time-frequency analysis, using the stationary wavelet transform to denoise the FBG reflection spectrum signal, and compared with the conventional discrete wavelet transform denoising effect. The results show that the SNR of this method is 3 dB higher than that of ordinary discrete wavelet transform and the mean square error is only 1/4 of that of ordinary discrete wavelet transform. Moreover, the method guarantees the peak value of the FBG reflection spectrum after de-noising, that is, the corresponding center wavelength, and overcomes the defect that the non-linear phase and the non-translation are not changed due to the downsampling operation of the ordinary discrete wavelet transform.