估计员
瞬时相位
多普勒效应
概率密度函数
信号(编程语言)
统计
概率分布
频率偏差
数学
标准差
声学
超声波传感器
直方图
物理
自动频率控制
计算机科学
电信
雷达
天文
人工智能
图像(数学)
程序设计语言
出处
期刊:IEEE Transactions on Biomedical Engineering
[Institute of Electrical and Electronics Engineers]
日期:1981-11-01
卷期号:BME-28 (11): 733-741
被引量:64
标识
DOI:10.1109/tbme.1981.324853
摘要
The relationship between the instantaneous frequency and the mean frequency of ultrasonic Doppler signals in blood velocity measurements is discussed. The probability distribution density for the instantaneous frequency is calculated. The time interval histogram (TIH), which has been used to characterize the Doppler signal, is found to be an approximation of this probability density. The probability density will also describe the output of phase-lock loop analysis of the Doppler signal. The variance of mean frequency estimators is calculated, and the implication of this for practical estimators is discussed. The effect of hard limiting of the signal on the estimator performance is also discussed.
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