| 摘要 |
PURPOSE:To improve the ripple characteristics within the pass band by satisfying the relation of N=F/R<2>, where N is the electrode logarithm, F is the constant of the substrate and R<2> is the electro-mechanical coupling coefficient each. CONSTITUTION:The elastic surface wave radiated from sending-end transducer 1 reaches receiving-end transducer 2 to be changed into the electric signal. In this case, if the mismatching occurs, the re-excitation is given to the elastic surface wave at transducer 2 to cause the interference and then the ripple. If the perfect impedance matching is secured for either the receiving end or the seding end or for both of them, no ripple is caused. In this connection, the simultaneous matching is secured for both the phase angle and the absolute value of the impedance by deciding each value of electrode logarithm N, constant F of the substrate and electro- mechanical coupling coefficient R<2> to satisfy the relation of N=F/R<2>. |
