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文章提出双频超声波多普勒血流量测量的理论模型,并加以理论证明,在此基础上通过Matlab对其进行仿真,得到双频超声波多普勒血流量测量的理论结果。即两束多普勒信号虽然载波的频率不同,但是经过带通滤波和低通滤波等一系列处理后,两束多普勒频移信号的频谱分布规律没有发生改变。经运算可使多普勒频移信号得到加强,而噪声信号的功率谱得到有效抑制。
In this paper, a theoretical model of dual-frequency Doppler blood flow measurement is proposed and theoretically proved. Based on this, the simulation results of this method are given by Matlab, and the theoretical results of dual-frequency Doppler blood flow measurement are obtained. That is to say, although two carrier Doppler signals have different carrier frequencies, the spectrum distribution of the two Doppler shift signals has not changed after a series of processing such as band-pass filtering and low-pass filtering. Doppler shift signal can be enhanced by the operation, and the power spectrum of the noise signal is effectively suppressed.