Optimizing Student Learning And Retention Of Time And Frequency Domain Concepts Through Numerical Computation Projects

Abstract

The ability to analyze signals and systems in both the time and frequency domains is an essential outcome in most engineering curricula. However, concepts such as time-domain convolution and frequency-domain spectra can be elusive to students. While most students can learn the mathematical procedures whereby they obtain correct answers on homework and exams, many lack the higher-level understanding that aids long-term retention. This paper addresses the creation of MATLAB and C projects that facilitate learning in these areas by clearly stating learning objectives, maintaining student interest with real-world applications, partitioning large projects into incremental modules, and providing the repetition necessary for long-term retention. The underlying assumptions for this work are twofold: (1) if a student can write the numerical software to solve a problem, they understand the theoretical principles well and (2) students receive personal satisfaction and gain confidence when their software produces correct results. The illustrative time-domain projects described here address linear convolution and trigonometric/exponential Fourier series. The frequency-domain projects address the computation of discrete Fourier transforms, spectral assessment, and time-frequency analysis. Real-world applications such as filter cascades for signal conditioning, tone control knobs for audio systems, and parameter extraction from biomedical signals drive these multi-week efforts. Typically assigned in the junior and senior years of the undergraduate curriculum, these efforts are precursors to upper-level undergraduate and graduate projects that incorporate full user interfaces. Through end-of-year evaluations and postgraduate feedback, many students refer to these projects as the highlight of their course experience.

A Small, High Fidelity Reflectance Pulse Oximeter

“…The structure of the Fall 2006 laboratory experience was unchanged relative to previous course offerings that utilized the former pulse oximeter design. 3,4 In terms of assessment, the primary goals were therefore two-fold: (1) to ensure that the learning objectives were met given the insertion of a new device design into the learning experience and ( 2) to gauge the level of improvement in learning and/or interest incurred by the insertion of the technically improved device. The primary assessment addressed the seven learning objectives introduced in section III.…”

“…Plug-and-play, reflectance pulse oximeters have been previously designed and utilized by this group for multiple education and research applications. [3][4][5][6][8][9][10] The functional block diagram that forms the basis for the previous designs is illustrated in Figure 1. The light-feedback-based approach 7 in Figure 1 drives the LED excitation sources with ever changing currents with a goal of maintaining a constant level for the amount of light that actually reaches the photodiode detector.…”

“…This makes them ideal targets for educational design projects and independent research efforts at both the undergraduate and graduate levels. 3,4 This paper addresses the design and educational application of a small, surface-mount pulse oximeter that incorporates an optimized light excitation/collection geometry and employs a Universal Serial Bus (USB) connection to a LabVIEW virtual instrument running on a personal computer. Reflectance plethysmograms from this sensor are unfiltered and demonstrate high fidelity compared to previous designs.…”

“…Data obtained from these sensors are used in undergraduate/graduate learning experiences and research investigations that address (a) the fundamental principles of pulse oximeter operation and data analysis, (b) extraction of hemodynamic parameters that map to user state of health, (c) the use of different digital filters to extract signal noise and motion artifact, (d) assessment of wearer identity based upon the timeand frequency-domain characteristics of plethysmographic signals, etc. [3][4][5][6] Most commercial pulse oximeters do not provide access to plethysmographic data, even if they display these data on their front panels. For units that provide these data, the filters applied to these pulsatile data are proprietary (and therefore unknown) and can have a significant bearing on the information contained in the resultant data, which equates to data loss and ultimately confusion regarding how to interpret these signals.…”

Portable Cyber Laboratories For Electrical Engineering Education

“…The investigators on this project have a history of creating effective learning tools for engineering education. [14][15][16][17][18][19][20][21][22][23][24][25][26] One recent product, a RASCL unit, 24 is an analog/digital prototyping tool that forms the initial hardware and software technology base for the learning modules proposed here. It was designed to allow students to complete hands-on laboratory assignments off-campus.…”