Sound pulse specular reflection echo and their curvature effect of boundary surface

In this paper, from the relationship between the time range construct of pulse echo from a rigid sphere and surface distribution, the curvature effect of boundary surface of a target on the wave-form of the specular reflecting echo from the surface and sound reflecting from an edge are studied. In high frequency range, the specular reflection echo have the same wave form as the incident wave, but in low frequency range or resonance scattering range, there is a time expansion of the pulse width after main reflecting echo from smooth curvature surface. Since the time expansion is caused by the curvature surface, it is regarded as the curvature effect, which is relative to frequency and reflective angle. The transmission function of a curved edge is in inverse proportion to 1/2 power of frequency, so the reflective wave-forms have the distortion known as the effect of an edge. But the reflecting wave-forms from a straight edge are the same as impinging wave-forms.