【摘要】 小波式叉指换能器使用机电耦合系数比较大的基片(如YZ-L iNbO3基片)时,其频率特性曲线不光滑,但插入损耗小;小波式叉指换能器使用机电耦合系数比较小的基片(如X 112°Y-L iTaO3基片)时,其频率特性曲线光滑,但插入损耗大.声表面波器件的指条对数N越少,其带宽Δf/f越大,插入损耗越大,所以,指条对数N要取的合适,不宜过少.在声表面波式小波变换器件中,发射叉指换能器的条对数N取57,接收叉指换能器的指条对数是57的四分之一到三分之一之间.更多还原

【Abstract】 If the substrate of largerelectromechanical coupling coefficient(suchas YZ-LiNbO3substrate)is used forwavelettype ofinterdigital transducer(IDT),its frequency characteristic curve is notsmooth,butits in-sertion loss is smaller.If the substrate of smaller electromechanical coupling coefficient(such as X 112°Y-LiTaO3substrate) is used forwavelettype ofIDT,its frequency characteristic curve is smooth,butits insertionlossis larger.The less the finger pairsNof surface acoustic wave(SAW) element,the larger its bandwidthΔf/f,andthe largerits insertionloss,so the fingerpairsNis appropriately taken,and is nottoo small.Inwavelettransformel-ement of SAW type,the finger pairs N of the transmitting IDT is 57,the finger pairs N of the receiving IDT is be-tween one-fourth of57 and one-third of57.更多还原