SUPPRESSION OF EDGE WAVES BY APODIZATION OF WIDE BAND CYLINDRICAL TRANSDUCERS

摘要

It was shown experimentally that the edge wave suppression can be obtained by the apodization of the transducer. We developed and evaluated transducers with a saw tooth shape edge of the electrode, but obviously other shapes can be proposed. The modified transfer functions of the apodized transducers are narrower than the parent transfer function. For V(z,t) measurements, the time of flight of edge waves is always larger than the time of flight of leaky waves. Therefore, a moderate apodizartion of the transducer can be recommended in this case. On the contrary, the edge wave responses are in the area of interest of the V(x,t) data, thus strong apodization is more effective for two transducers configuration.