Tianjin University, School of Precision Instrument and Opto-Electronics Engineering, Tianjin 300072, China.
J Biomed Opt. 2013 May;18(5):57003. doi: 10.1117/1.JBO.18.5.057003.
An appropriate method for spectrum extraction for better signal-to-noise ratio (SNR) and lower computational cost is essential in noninvasive detection. We have first studied two existing extraction methods for dynamic spectrum (DS) comparatively: frequency domain analysis and single trial estimation; after analyzing the advantages and disadvantages theoretically, a new method based on a fast digital lock-in amplifier (FDLIA) was developed to overcome the limitations of these two existing methods. The feasibility of the new method was verified by experiments and the results demonstrated that the FDLIA method based on DS had greatly simplified the computation of frequency domain analysis without the method error; moreover, the continuous signal was cut into several short segments in FDLIA and the gross errors from an episode of pulse wave were eliminated, and thus SNR improved. Therefore, the FDLIA method utilizing the advantages of both existing methods can be effectively realized in a general embedded system in real time for its simple algorithm.
在无创检测中，为了获得更好的信噪比（SNR）和更低的计算成本，选择合适的频谱提取方法至关重要。我们首先对两种现有的动态频谱（DS）提取方法进行了比较：频域分析和单次估计；在从理论上分析了它们的优缺点之后，开发了一种基于快速数字锁定放大器（FDLIA）的新方法，以克服这两种现有方法的局限性。通过实验验证了新方法的可行性，结果表明，基于 DS 的 FDLIA 方法大大简化了频域分析的计算，而没有方法误差；此外，在 FDLIA 中，连续信号被分成几个短段，并且从一个脉冲波中消除了粗大误差，从而提高了 SNR。因此，该 FDLIA 方法利用了现有方法的优点，可以在通用的嵌入式系统中实时有效地实现，因为它的算法简单。
