DEVICE FOR MEASURING THE SPEED OF MOVING ORGANS AND BLOOD FLOWS BY ULTRASONIC ECHOGRAPHY

摘要

A first channel processes a received echo signal and comprises a first intercorrelation circuit for two successive echographic signals Sn(t) and Sn+1(t). A second, parallel channel comprises two symmetrical parallel bandpass filters responsive to the echographic signals for generating from each received signal two signals at a frequency f1<fo and f2>fo, respectively, and supplying sn1(t) and sn2(t). A multiplier forms sSn1(t)xsn2(t). A symmetrical low-pass filter selects the components sn(t) having the frequency f2-f1 of the multiplier product. A second intercorrelation circuit provides a correlation signal from the selected signal sn(t) and sn+1(t). A multiplexing/interpolation circuit supplies the value of the speed by searching for the maximum of the first correlation function in the vicinity of the maximum of the second correlation function.