Wang Hengliang, Siu Kin, Ju Kihwan, Chon Ki H
Department of Biomedical Engineering, State University of New York, Stony Brook, NY 11794-8181, USA.
Ann Biomed Eng. 2006 Feb;34(2):326-38. doi: 10.1007/s10439-005-9035-y. Epub 2006 Feb 7.
A high resolution approach to estimating time-frequency spectra (TFS) and associated amplitudes via the use of variable frequency complex demodulation (VFCDM) is presented. This is a two-step procedure in which the previously developed time-varying optimal parameter search (TVOPS) technique is used to obtain TFS, followed by using the VFCDM to obtain even greater TFS resolution and instantaneous amplitudes associated with only the specific frequencies of interest. This combinational use of the TVOPS and the VFCDM is termed the TVOPS-VFCDM. Simulation examples are provided to demonstrate the performance of the TVOPS-VFCDM for high resolution TFS as well as instantaneous amplitude estimation. The simulation results show that the TVOPS-VFCDM approach provides the highest resolution and most accurate amplitude estimates when compared to the smoothed pseudo Wigner-Ville, continuous wavelet transform and Hilbert-Huang transform methods. Application of the TVOPS-VFCDM to renal blood flow data indicates some promise of a quantitative approach to understanding the dynamics of renal autoregulatory mechanisms as well as a possible approach to quantitatively discriminating between different strains of rats.
本文提出了一种通过使用可变频率复解调（VFCDM）来估计时频谱（TFS）及相关幅度的高分辨率方法。这是一个两步过程，其中首先使用先前开发的时变最优参数搜索（TVOPS）技术来获取TFS，然后使用VFCDM来获得更高的TFS分辨率以及仅与特定感兴趣频率相关的瞬时幅度。TVOPS和VFCDM的这种组合使用被称为TVOPS-VFCDM。提供了仿真示例来证明TVOPS-VFCDM在高分辨率TFS以及瞬时幅度估计方面的性能。仿真结果表明，与平滑伪维格纳-威利、连续小波变换和希尔伯特-黄变换方法相比，TVOPS-VFCDM方法提供了最高分辨率和最准确的幅度估计。将TVOPS-VFCDM应用于肾血流数据表明，它有望成为一种定量理解肾自动调节机制动态的方法，以及一种定量区分不同大鼠品系的可能方法。
