Teaching Dsp Before Analog Signals: Some Unexpected Consequences

For many years our electrical engineering program’s required analog signal analysis course was taught before the Digital Signal Processing (DSP) elective. That has been the tradition at many universities. But while students would do an acceptable job in the analog course they would often express displeasure regarding the level of rigor required by the course. It was suspected that the calculus content of this first course dealt a blow making the material somewhat abstract. Plus, the course had no laboratory, so the only exposure to signals problems was “on paper.” Four years ago the EE program was changed significantly 1,2 to a model that includes teaching material on an as-needed basis. For example, we teach the ideal op amp topic to freshmen, delaying the details of the internal workings to a later course. The freshmen could then see the utility of, and use in simple designs, a powerful circuit tool. Another change was to institute DSP as a required course, and to be taught before the analog signals course. While this is somewhat non-traditional, it appeared to be a logical choice. The faculty generally believed that the mathematics in DSP was simpler than in analog signals – there is no calculus, and the math is mostly algebra with some infinite series concepts. It was believed that students would more readily grasp ideas of frequency content, spectrum, and filtering. Additionally, teaching DSP first 3 has been proven to be successful at other institutions. After two years of the new approach, the situation was assessed. As one measure, student grades in the analog signals course were examined in both the pre-DSP and post-DSP programs. Somewhat to our surprise, grades in the analog course decreased slightly, as a whole, with the DSP-first approach. The decrease was small but, more significantly, it was not the expected increase. Interestingly, examination of individual students showed that those who took DSP first had analog course grades that were distributed normally relative to their DSP grades – some improved, some declined. Personal interviews with these students revealed a variety of opinions on the merits of DSP-first and how that affects performance in the analog course. This assessment is a work in progress, and efforts have been identified to contribute to improved analog course performance success in using the DSP-first approach.