Title :
FM Doppler systems-experimental results
Author :
Wilhjelm, J.E. ; Pedersen, P.C.
Author_Institution :
Worcester Polytech. Inst., MA, USA
Abstract :
The authors demonstrate experimentally that a Doppler system transmitting repetitive coherent frequency-modulated signals (FM Doppler) can produce velocity profiles of the form known from a conventional pulsed-wave (PW) Doppler. The FM Doppler system utilizes two signal processing schemes that are similar to what is used in a PW Doppler. These two schemes are phase shift measurement and a method based on cross correlation. As coherent sweeps are used, vessel wall echoes can be removed by means of a stationary echo canceller. Simulations comparing the cross-correlation schemes for PW and FM and experiments comparing phase shift and cross-correlation measurements for both FM and PW Doppler systems are presented. With the present FM Doppler implementation, the accuracy of the PW Doppler appears to be better
Keywords :
Doppler effect; biomedical equipment; biomedical ultrasonics; haemodynamics; ultrasonic equipment; ultrasonic velocity measurement; FM Doppler systems; PW Doppler; experimental results; phase shift measurement; pulse-wave Doppler; repetitive coherent frequency-modulated signals; velocity profiles; Biomedical measurements; Biomedical signal processing; Chirp; Echo cancellers; Frequency measurement; Frequency modulation; Phase measurement; Pulse measurements; Time measurement; Velocity measurement;
Conference_Titel :
Ultrasonics Symposium, 1990. Proceedings., IEEE 1990
Conference_Location :
Honolulu, HI
DOI :
10.1109/ULTSYM.1990.171628
