| 摘要 |
FIELD: physics.SUBSTANCE: probing signal having a narrow main lobe of its autocorrelation function is transmitted into the medium and an echo signal is received; after receiving the echo signal, its autocorrelation function is obtained by matched filtering. The probing signal used is an arbitrary wideband signal and matched filtering is carried out for the repeatedly reflected echo signal in the range of the expected delays; the image of the propagation delays of the ultrasonic waves is presented as a result of multichannel matched filtering in form of a surface formed by time readings on the ordinate axis, the numbers and output signals of channels of the multichannel matched filter, respectively, on the abscissa and applicate axes.EFFECT: enabling distinction of multiple shear and longitudinal waves existing in an echo signal at the same time and independent measurement of propagation delays thereof.2 cl, 5 dwg |
