摘要
超声多普勒音频信号是一种非平稳时间序列 ,其功率谱是时变谱。为了能够准确有效地计算它的功率谱 ,要兼顾时间分辨力和时间窗截断效应。以前采用 10ms固定长度时间窗进行功率谱估计虽有其合理性但并不完善。本文利用线性调频信号研究超声多普勒信号的非平稳特性 ,并在此基础上得出了超声多普勒信号准平稳时间段随心动时相不同而不同的结论 ,为超声多普勒信号谱分析的时间窗选取提供依据。
The Doppler ultrasound signal is a non-stationary time sequence. Its power spectrum density is time-varying. It is nessecery to keep balance between the time resolution and the truncation effect of the time window. The former method, assuming 10 ms as the best time window length, had its rationality but not consummated. Here the linear frequency modulation signal was used to simulate the nonstationary features of Doppler ultrasound signal. It was shown that the time length of stationary segmentation of Doppler ultrasound signal was related to different phases of cardiac cycle, which could be used for window choice in Doppler signal spectral analysis.
出处
《中国生物医学工程学报》
EI
CAS
CSCD
北大核心
2000年第3期342-347,共6页
Chinese Journal of Biomedical Engineering
基金
国家自然科学基金
教育部博士点基金
关键词
超声多普勒
非平稳
功率谱
准平稳分段
Doppler ultrasound
Non-stationary
Power spectrum
Stationary segmentation
