基于相似匹配方法的布里渊频移提取算法具有无需预设模型、适应性强的优点。为了获得谱信号参数和扫频参数对算法性能的影响,在仅单一因素变化情况下系统研究了布里渊线宽(简称线宽)、信噪比、扫频间隔、扫频范围对布里渊频移提取准确性的影响规律。结果表明:频移误差与线宽成线性关系,探测谱与参考谱线宽差距本身对算法准确性产生的影响较小;频移误差随参考谱和探测谱信噪比的增加均呈指数规律减小;扫频间隔不变时随参考谱扫频范围增加频移误差存在增加的趋势,同时计算时间线性增加;探测谱的扫频范围为2倍线宽时频移误差最小。研究结果可为布里渊频移的准确提取提供参考。

The Brillouin frequency shift extraction algorithm based on similarity matching method exhibits considerable adaptability and does not require a predefined model. In this study, the influence of the Brillouin linewidth (short for linewidt), signal-to-noise ratio, sweeping step, and sweeping range on the extraction accuracy of the frequency shift is systematically studied by varying each factor to obtain the influence of the spectral signals and sweep parameters on the performance of the algorithm. The frequency shift error is a linear function of the Brillouin linewidth. The linewidth difference between the selected detected spectrum and the selected reference spectrum does not considerably affect the accuracy of the algorithm. When the signal-to-noise ratio of the selected detected spectrum remains constant, the frequency shift error decreases exponentially with the increasing signal-to-noise ratio of the selected reference spectrum, and vice versa. When the frequency sweep step is maintained constant, the frequency shift error increases with the increasing sweep range of the selected reference spectrum; this is accompanied by a linear increase in the calculation time. The frequency shift error is the smallest when the frequency range of the selected detected spectrum is twice the linewidth. Furthermore, the obtained results can provide a reference for the accurate extraction of Brillouin frequency shift.