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arXiv 2312.13643stat.MEmath.STstat.TH
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用于谱密度估计的Welch方法去偏

Debiasing Welch's Method for Spectral Density Estimation

Lachlan C. Astfalck, Adam M. Sykulski, Edward J. Cripps

AI总结:

针对Welch功率谱密度估计中分段数设置的偏差-方差权衡问题,提出保留原计算复杂度与渐近一致性的去偏方法,可显著降偏,支持不规则频率间隔,配套R和python代码。

摘要:

Welch方法可提供具有统计一致性的功率谱密度估计量,这一特性通过对时间序列重叠分段计算得到的周期图取平均来实现。对于有限长度的时间序列,虽然估计量的方差会随分段数量增加而减小,但估计量的偏差幅度会增大:在设定分段数量时会出现偏差-方差权衡问题。我们提出了一种用于Welch方法去偏的新方法来解决该问题,该方法保留了原方法的计算复杂度与渐近一致性,且能提升有限样本下的性能。本文针对具有有限四阶矩、四阶累积量函数绝对收敛的四阶平稳过程给出了理论结果。通过数值模拟与真实数据应用验证了该方法可显著降低偏差。我们的估计量还支持频率上的不规则间隔,本文展示了该特性可如何用于信号压缩与进一步降低方差。本工作配套代码已提供R与python版本。

英文摘要:

Welch's method provides an estimator of the power spectral density that is statistically consistent. This is achieved by averaging over periodograms calculated from overlapping segments of a time series. For a finite length time series, while the variance of the estimator decreases as the number of segments increase, the magnitude of the estimator's bias increases: a bias-variance trade-off ensues when setting the segment number. We address this issue by providing a novel method for debiasing Welch's method which maintains the computational complexity and asymptotic consistency, and leads to improved finite-sample performance. Theoretical results are given for fourth-order stationary processes with finite fourth-order moments and absolutely convergent fourth-order cumulant function. The significant bias reduction is demonstrated with numerical simulation and an application to real-world data. Our estimator also permits irregular spacing over frequency and we demonstrate how this may be employed for signal compression and further variance reduction. Code accompanying this work is available in R and python.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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