7.1 Design of Discrete-Time IIR Filters From continuous-Time filters The traditional approach to the design of discrete time iir filters involves the transformation of a continuous-time filter into a discrete filter meeting prescribed specification
17 7.1 Design of Discrete-Time IIR Filters From Continuous-Time Filters ◆The traditional approach to the design of discrete-time IIR filters involves the transformation of a continuous-time filter into a discrete filter meeting prescribed specification
Three reasons 1 The art of continuous-time iir filter design is highly advanced, and since useful results can be achieved it is advantageous to use the design procedures already developed for continuous-time filters 18
18 Three Reasons 1. The art of continuous-time IIR filter design is highly advanced, and since useful results can be achieved, it is advantageous to use the design procedures already developed for continuous-time filters
Three reasons 2. Many useful continuous-time IIR design method have relatively simple closed form design formulas. Therefore, discrete-time iir filter design methods based on such standard continuous-time design formulas are rather simple to carry out 19
19 Three Reasons 2. Many useful continuous-time IIR design method have relatively simple closed form design formulas. Therefore, discrete-time IIR filter design methods based on such standard continuous-time design formulas are rather simple to carry out
Three reasons 3. The standard approximation methods that work well for continuous-time iiR filters do not lead to simple closed-form design formulas when these methods are applied directly to the discrete-time iir case because the frequency response of a discrete-time filter is periodic, and that of a continuous-time filter is not
20 Three Reasons 3. The standard approximation methods that work well for continuous-time IIR filters do not lead to simple closed-form design formulas when these methods are applied directly to the discrete-time IIR case, ➢ because the frequency response of a discrete-time filter is periodic, and that of a continuous-time filter is not
Steps of DT filter design by transforming a prototype continuous-time filter ◆① Obtain the specifications for continuous time filter by transforming the specifications for the desired discrete-time filter ◆② Find the system function of the continuous-time filter ◆③ Transform the continuous-time filter to derive the system function of the discrete-time filter 21
21 Steps of DT filter design by transforming a prototype continuous-time filter ◆① Obtain the specifications for continuoustime filter by transforming the specifications for the desired discrete-time filter. ◆② Find the system function of the continuous-time filter. ◆③ Transform the continuous-time filter to derive the system function of the discrete-time filter