The Coding Of Sound By A Cochlear Prosthesis: An Introductory Signal Processing Lab

An innovative and pedagogically appealing real-world application—a cochlear implant signal processor—forms the substrate for a laboratory exercise in design, simulation, and qualitative assessment of an engineering problem. In an introductory signal processing course, students are able to write MATLAB code that mimics the operation of a cochlear implant signal processor in which sound information is extracted and then coded for input to a neural stimulator. Fundamental concepts such as sampling continuous-time signals, discrete-time filter design, filter banks, envelope detection, spectrograms and signal reconstruction are explored and formalized in different parts of this project. To promote interaction across disciplines, the students work in randomly assigned teams of two that often pair up Biomedical Engineering (BME) students with Electrical and Computer Engineering (ECE) students. For many students, the lab presents the first exposure to a collaborative engineering design effort, in contrast to the common independent exercise of tackling a “tough homework problem.” Although this laboratory project is quite challenging, it was well liked by the diverse population of BME and ECE students. Efforts are underway to integrate an online post-lab survey during the upcoming term to enable a more quantitative means of assessment. In addition, to provide free international access, the laboratory will be disseminated on the Connexions educational website.