EE345S Real-Time Digital Signal Processing Laboratory - Overview

Prof. Brian L. Evans

Through this undergraduate elective, I hope that students gain an intuitive feel for basic discrete-time signal processing concepts and how to translate these concepts into real-time software using digital signal processor technology. The course will review some of the mathematical foundations of the course material, but emphasize the qualitative concepts. The qualitative concepts are reinforced by hands-on laboratory work and homework assignments.

In the laboratory and lecture, the course will cover

In particular, we will discuss design tradeoffs between implementation complexity and signal quality/communication performance.

In the laboratory, students will design, implement, and test transceiver subsystems to reach the ultimate goal of building a v22.bis voiceband modem. A v22.bis modem reference design is available as a LabVIEW demonstration and block diagram. In implementing the v22.bis transceiver, students will be writing C language software for the TI TMS320C6701 digital signal processor (DSP), which is a floating-point member of the TI C6000 DSP family. The C6000 family is used in DSL modems, wireless LAN modems, mobile wireless basestations, video conferencing systems, and professional audio systems. For professional audio systems, the C6700 floating-point sub-family empowers guitar effects and intelligent mixing boards. In developing and debugging the software, students will use the TI Code Composer Studio. Students will test and measure characteristics of their implementations by using LabVIEW running on the host PC and external equipment.

In addition to learning about voiceband modem design in the lab and lecture, students will also learn in lecture about the design of modern analog-to-digital and digital-to-analog converters, which employ oversampling, filtering, and dithering to obtain high resolution. Whereas the voiceband modem is a single carrier system, lectures will also cover modern multicarrier modulation systems, esp. asymmetric digital subscriber line (ADSL) and wireless LAN systems. In particular, we discuss the data transmission subsystems in ADSL and wireless LAN transceivers. Last, we spend several lectures on digital signal processor architectures, esp. the architectural features adopted to accelerate digital signal processing algorithms.

For the lab component, I chose a floating-point DSP over a fixed-point DSP. The primary reason was to avoid overwhelming the students with the severe fixed-point precision effects so that the students could focus on the design and implementation of real-time digital communications systems. That said, floating-point DSPs are used in industry to prototype algorithms, e.g. to see if real-time performance can be met. If the prototype is successful, then it might be modified for low-volume applications or it might be mapped onto a fixed-point DSP for high-volume applications (where the engineering time for the mapping can potentially be recovered).

From Fall 1997 to Spring 2002, the course used the TMS320C3x family of floating-point DSPs. At that time, some companies were actively using this DSP family. For example, Southwestern Research Institute in San Antonio, TX, under contract from SAIC, built a VME card cage containing a single processor, military specification TMS320C30 for the infrared satellite imaging subsystem. As another example, Dr. Thomas P. Barnwell (Atlanta Signal Processors Inc., Atlanta, GA, now part of Polycom) prototyped a DirectTV decoder on a TI TMS320C31 floating-point DSP before it was implemented on a fixed-point processor.

A UT undergraduate student who took the real-time DSP laboratory course in Fall 1999 and graduated in May of 2000 wrote the following about the course in August 2000:

"... keep that real-time DSP lab as good as it was when I took it. I have to say, that lab was the best class I took at UT. It is close enough to the cutting edge of technology that you can hold a conversation with someone from industry and actually contribute useful ideas. 345L is a close second. Good work."

This alumnus works at a medium-sized high-tech company.


Last updated 12/07/04. Send comments to (Mailbox)