[Effects of a high-pass filter on the Doppler blood flow signal].
A high-pass filter is used to remove the large signals scattered or reflected from stationary and slow moving objects in many clinical CW Doppler units. theoretical results are presented that such a filter will lead to overestimate of the mean velocity of Doppler blood flow. As for different frequency signals, high-pass filter have different amplitudes and phase responses, consequently, nonlinear phase shift is produced. It is proved by computer experiment that nonlinear phase shift caused by high-pass filter hardly has any effects on Doppler flow power spectrum if the high-pass filter does not affect the amplitudes of signals.
Wen
Y
Y
Dept of Biomedical Engineering, Xi'an Jiaotong University.
Qian
M
M
Gong
X
X
Zhen
B
B
Wan
M
M
D001783:Blood Flow Velocity; D003198:Computer Simulation; D004582:Electronics, Medical; D008433:Mathematics; D018608:Ultrasonography, Doppler