DSP_Chapter09

CHAPTER 9 IIR Digital Filter Design CHAPTER 9 IIR Digital Filter Design YANG Jian nxryang@126.com School of Information Science and Technology Yunnan University 2008-03 ~ 2008-07 云南大学课程：数字信号处理 Digital Filter Design 2 OutlineOutline • Preliminary Considerations • Bilinear Transformation Method of IIR Filter Design • Design of Lowpass IIR Digital Filters • Design of Highpass IIR Digital Filters • IIR Digital Filter Design Using MATLAB • Computer-Aided Design of Digital Filters • Summary 云南大学课程：数字信号处理 Digital Filter Design 3 Preliminary ConsiderationsPreliminary Considerations 云南大学课程：数字信号处理 Digital Filter Design 4 Digital Filter SpecificationsDigital Filter Specifications 云南大学课程：数字信号处理 Digital Filter Design 5 Digital Filter SpecificationsDigital Filter Specifications 云南大学课程：数字信号处理 Digital Filter Design 6 Digital Filter SpecificationsDigital Filter Specifications 云南大学课程：数字信号处理 Digital Filter Design 7 Selection of the Filter TypeSelection of the Filter Type More efficientComputation Exact linear phasePhase response Zeros and polesZeros OnlyZero-poles FeedbackNo feedbackStructure H(z) = P(z) / D(z)H(z) = P(z)System Function InfiniteFiniteImpulse Response IIR DFFIR DF 云南大学课程：数字信号处理 Digital Filter Design 8 Bilinear Transformation Method of IIR Filter Design Bilinear Transformation Method of IIR Filter Design • Bilinear transformation is more commonly used to design IIR digital filters based on the conversion of analog prototype filters. • The Bilinear Transformation – The bilinear transformation from the s-plane to z-plane is given by – The transformation is a one-to-one mapping. It maps a single point in the s-plane to a unique point in the z-plane. – The relation between the digital transfer function G(z) and the parent analog transfer function Ha(s) is given by 1 1 2 1( ) 1 zs T z − − −= + 12 1 11 ( ) ( ) ( ) z T z a s G z H s −− −+ == 云南大学课程：数字信号处理 Digital Filter Design 9 Bilinear TransformationBilinear Transformation 云南大学课程：数字信号处理 Digital Filter Design 10 Bilinear TransformationBilinear Transformation 云南大学课程：数字信号处理 Digital Filter Design 11 Bilinear TransformationBilinear Transformation 云南大学课程：数字信号处理 Digital Filter Design 12 Bilinear TransformationBilinear Transformation 云南大学课程：数字信号处理 Digital Filter Design 13 Bilinear TransformationBilinear Transformation 云南大学课程：数字信号处理 Digital Filter Design 14 Bilinear TransformationBilinear Transformation 云南大学课程：数字信号处理 Digital Filter Design 15 Design of Lowpass IIR Digital FiltersDesign of Lowpass IIR Digital Filters 云南大学课程：数字信号处理 Digital Filter Design 16 Design of Lowpass IIR Digital FiltersDesign of Lowpass IIR Digital Filters 云南大学课程：数字信号处理 Digital Filter Design 17 Design of Lowpass IIR Digital FiltersDesign of Lowpass IIR Digital Filters 云南大学课程：数字信号处理 Digital Filter Design 18 Design of Lowpass IIR Digital FiltersDesign of Lowpass IIR Digital Filters 云南大学课程：数字信号处理 Digital Filter Design 19 Design of Lowpass IIR Digital FiltersDesign of Lowpass IIR Digital Filters 云南大学课程：数字信号处理 Digital Filter Design 20 Design of Highpass IIR Digital FiltersDesign of Highpass IIR Digital Filters • The first approach – Step 1: Prewarp frequency, GD(z) to the same type HD(s) – Step 2: Convert HD(s) to the prototype analog lowpass filter HLP(s) – Step 3: Design the prototype analog lowpass filter HLP(s) – Step 4: Convert HLP(s) into HD (s) – Step 5: Transform HD (s) to GD(z) by bilinear transformation 云南大学课程：数字信号处理 Digital Filter Design 21 Design of Highpass IIR Digital FiltersDesign of Highpass IIR Digital Filters 云南大学课程：数字信号处理 Digital Filter Design 22 Design of Highpass IIR Digital FiltersDesign of Highpass IIR Digital Filters 云南大学课程：数字信号处理 Digital Filter Design 23 Design of Highpass IIR Digital FiltersDesign of Highpass IIR Digital Filters 云南大学课程：数字信号处理 Digital Filter Design 24 IIR Digital Filter Design Using MATLABIIR Digital Filter Design Using MATLAB • Signal Processing Toolbox of MATLAB • Order Estimation – buttord, cheb1ord, cheb2ord, ellipord – Example 9.10, 9.11 • Filter Design – butter, cheby1, cheby2, ellip – Example 9.12, 9.13, 9.14 – Program 9_1.m, Program 9_2.m, Program 9_3.m 云南大学课程：数字信号处理 Digital Filter Design 25 SummarySummary • IIR filter design • Signal Processing Toolbox of MATLAB • ? • ? 云南大学课程：数字信号处理 Digital Filter Design 26 Assignment and ExperimentAssignment and Experiment • Assignment – 第九章： • 9.3，9.4，9.5， 6月25日交。 • Experiment – 实验七：数字滤波器 设计 领导形象设计圆作业设计ao工艺污水处理厂设计附属工程施工组织设计清扫机器人结构设计 （第7章） • 6月18日：Q7.1，Q7.2，Q7.3, Q7.4。 • 6月25日：Q7.5，Q7.6，Q7.7，Q7.8。