离散傅里叶变换在SAW滤波器衍射补偿中的应用  

Application of DFT in SAW Filter Diffraction Compensation

作　　者：叶程都[1] 覃亚丽[1] 

机构地区：[1]浙江工业大学信息工程学院,浙江杭州310014

出　　处：《电声技术》2008年第3期69-72,共4页Audio Engineering

摘　　要：在Fresnel积分和各向异性抛物线近似下,用δ函数模型分析了由一个变迹IDT和一个均匀IDT组成的声表面波(SAW)带通滤波器衍射频响的计算方法,推导了滤波器采样频响的离散傅里叶反变换与变迹IDT叉指交叠长度序列的对应关系,并根据衍射频响和理想频响的差值计算出需要修正的变迹IDT叉指交叠长度序列的大小,通过迭代校正对衍射效应进行补偿。数值仿真结果表明,由衍射效应引入的滤波器频响带外恶化基本得到消除。For SAW（Surface Acoustic Wave） bandpass filters consisting of one apodized and one unapodized IDT （Interdigital Transducer）, the frequency response including diffraction effects is analyzed based on δ-function model if the Fresnel and parabolic-anisotropy approximation are allowed. The corresponding relationship between the inverse DFT（Discrete Fourier Transform） and the apodized transducer is introduced, and the corrections to the taps of the apodized transducer are computed from the deviations of the diffracted frequency response from the desired response. Thus, the taps of the apodized transducer can be corrected iteratively so that the diffracted frequency response is close to the desired response. The simulation results show that this method is successfully applied to remove the deviations caused by diffraction effects.

关 键 词：离散傅里叶变换 声表面波滤波器 衍射补偿 

分 类 号：TN713[电子电信—电路与系统]