Teaching Speech and Audio Processing Implementations Using LabView Program and DAQ Boards

Abstract

We present our new pedagogy for teaching speech and audio processing implementations using LabView program and DAQ (Data Acquisition) board. In the Electrical and Computer Engineering Technology (ECET) curriculum, the LabView program and DAQ board data acquisition have been used as a popular platform for teaching a real-time DSP (digital signal processing) course in the junior year. This course is the second signal processing course which is offered in electrical and computer engineering technology (ECET) program according to the current DSP industry trend and student interests in their career development. The course has a significant component on real-time filtering applications. The pre-requisite includes student working knowledge and skills of Laplace transform, Fourier series, Fourier transform, and different types of analog active filter design. After completing the course, students not only become familiar with MATLAB and LabView software development tools, but also gain the real-time signal processing experience. They are able to design the low-pass and band-pass filters and then program them using MATLAB and LabView software, and apply the software and hardware interface for real speech applications. Comparing with the traditional DSP course which mainly focus on heavy mathematical development in sampling and recovering, spectrum analysis, FIR or IIR filter design with the limited computer simulations, our real-time speech project allow students easily to understand how his/her own voice could be enhanced (by an audio amplifier), digitized and collected (by a PCI-1200 DAQ board), displayed(by LabView and spectrum analyzer), processed(by MATLAB and LabView software), and recovered (by an active 2 nd -order lowpass filter). Therefore, in this paper, we first proposed a complete DSP platform, which consists of an LM386 audio amplifier, an analog lowpass filter, a PCI-1200 DAQ board interface circuit, and a DSP software to perform the real-time data processing. Using the proposed DSP platform, we present our instructional techniques for digital filter implementations in which an FIR lowpass filter and an IIR bandpass filter were designed and tested for real time processing. The student survey results show that the adoption of LabView and DAQ boards to teach DSP and digital filter design is a learning effective tool.