Computer-Aided Design (CAD) of Recursive/Non-recursive Filters

• Published in: Association for Engineering Education - Engineering Library Division Papers p. 26.385.1
• Main Authors: Xu, Chengying, S. Hossein Mousavinezhad
• Format: Conference Proceeding
• Language: English
• Published: Atlanta American Society for Engineering Education-ASEE 14.06.2015
• Subjects: Algorithms; CAD; Computer aided design; Computer simulation; Design engineering; Digital computers; Digital filters; Digital imaging; Digital signal processing; Digital systems; Digitization; Engineering; Engineering education; Frequency response; IIR filters; Image filters; Image processing; Mathematical analysis; Mathematical functions; Prototypes; Students; Video; Window functions
• DOI: 10.18260/p.23724

Computer-Aided Design (CAD) of Recursive/Non-Recursive Filters ABSTRACTComputer Tools are integral part of many engineering design courses, they should be used in theright place, right time. Courses in the Digital Signal Processing/Filter areas (including speech,image and video processing) have been traditionally viewed by students to be fairlymathematical subjects including many abstractions (like spectrum, analysis/design methods intime/frequency domains, SNR, bandwidth, white/pink noise, various transforms, etc.) With thehelp of modern engineering tools, engineering educators can better help students visualize theseapparently difficult (but important) concepts. In this paper we will focus on the subject ofdesigning digital filters, both with and without feedback, as well as analog prototypes. Inaddition to the use of popular software packages like MATLAB & MATHCAD, our filter courseuses a tool accompanying the textbook that can help students with various designs of thesedigital, analog systems and at the same time (in case of analog “prototype”) come up with Pspicecircuit elements as well as providing frequency response plots, pole/zero diagram.Starting with the input/output (I/O) models of these systems, students are gradually introduced tousing these CAD tools that can be beneficial in their work. For example after “digitizing” thedifferential equation of the system, they can solve the I/O model (linear, constant-coefficientdifference equation) of the system, hopefully (in some cases) by both doing a paper design andvalidating the design with computer simulation. The digital I/O models include both recursiveand non-recursive systems. For the CAD design there is a need for utilizing window functions,one important class of windows require the use of high-level mathematical functions for whichan algorithm is introduced so that students can come up with their final design and again use thesoftware tool for the verification step. Whenever possible students are given opportunity to makepresentation in the class where more results can be discussed and a term paper/report submittedto receive credit toward their grades. Since the required subjects/topics are very complex bynature these tools can be very beneficial for both learners and engineering educators. Finallythere are cases that a regular design employing the so-called classical system approach may notbe practical, however it will be possible to design the system using, for example, non-recursive,digital systems.