Dr Janse van Rensburg created online assignments in MATLAB Grader for her Linear Systems course. The purpose of this was to quickly and efficiently measure whether students understood the theory for designing a passive filter, before moving into the lab to build a physical passive filter. The MATLAB Grader assignments enabled a more efficient workflow as the lecturer could track her students’ understanding and application of theory.
Firstly, the lecturer needed to reduce the time spent during lab tests, when students would test the filter designs they had programmed using MATLAB. Time and resources were wasted during lab sessions because students struggled to design low and high-pass filters that worked. Additional lab sessions would have to be booked over a week or two-week period so that students would have the opportunity to correctly design filters, test them and receive feedback from the marked assignment.
Secondly, the assignment took too long to grade and provided little insight of the students theoretical and practical understanding of Linear Systems and passive filter design. Additionally, students were frustrated by the delayed feedback via graded assignments and would consequently press the lecturer, outside lecture and lab times, for additional assistance and feedback on the assignment and the theory.
Main steps in workflow
Dr Janse van Rensburg transferred the old course design of “pen and paper” to a Passive Filter Design assignment into a MATLAB Grader Course. The assignments were accessible for the duration of the course and the number of submissions were unlimited. This workflow was designed to enable continuous learning as it allowed students to consistently test the design of their passive filters and enabled access to theoretical information throughout the course.
The lecturer created two assignments. The first assignment was to introduce students to MATLAB Grader and familiarise them with step and impulse functions in MATLAB. The purpose of the second assignment was to design first-order passive filters in MATLAB without the use of a specialised toolbox like Signal Processing or DSP Toolbox. Students were expected to design a low-pass filter (Problem 1) and a high-pass filter (Problem 2) according to a client’s specifications.
Upon completing the MATLAB Grader Course, students practical tested their Passive Filter Designs in the lab with circuits they built and tested. Having completed the series of lectures, the MATLAB Grader Assignments and practical lab session, students were requested to hand in a report detailing the design, verification, validation and conclusions of the passive filter.
Results of using Opti-Num Solutions Products and Services
Students were able to (1) explore the theory and research the fundamental methods of design, (2) apply the theory in a safe and interactive environment, (3) test their application and iteratively improve their design. The use of MATLAB Grader for online assessment saved time as lab sessions were reduced by more than 50% because the students knew what to expect after completing their designs in MATLAB Grader. Students could easily test and verify their MATLAB code, their filter design and theoretical understanding throughout the course, all before the practical lab sessions took place. It also reduced student frustration with theory due to interactive feedback through pre-tests in MATLAB Grader.
If the filter design did not work during the practical, both lecturer and student could be sure that it was not the code that was wrong but rather the circuit components. These mistakes were easily identifiable and fixed during a single lab session. With this approach, the quality of students’ designed filters was much higher where this design occurred outside of the lab and rather in their own interactive environment of MATLAB Grader. Time and components were saved due the higher quality of design before practical implementation.