The next several weeks in lab will be devoted to the design and development of a project related to signals and systems. You are free to choose the topic for your project. Some suggested topics are listed on this handout. You will have the opportunity to give an oral presentation of your project, and you will submit a written report.

Please list some potential project ideas before leaving lab today.

First, please finish some items from Lab 5:

1. Make sure your Sun accounts are set up to use the dSPACE boxes. Go through the steps of programming the dSPACE box from a C program. (Programming the dSPACE boxes from Simulink is currently not available.) Input a sine wave to the dSPACE box, and view the input and output waves on the oscilloscope. What happens when you increase the sine wave frequency beyond one-half the sampling rate? You might want to attach a speaker to the dSPACE output when you do this experiment.
2. Develop and execute on dSPACE the C programs that add and subtract adjacent samples, as described on Lab 5 assignment. Process some real signals (sine waves, square waves, triangle waves, speech, music) with these digital filters.
3. Review the descriptions of some past projects from the 1994 and 1995 Signals and Systems course described at
   http://www.eg.bucknell.edu/~kozick/ili/ili.html
   
4. Take notes so that you will be able to use the dSPACE box in your project (if your project can be implemented in real-time).

Design Project Overview

You can work on the project individually, or in groups of two or three. Projects from larger groups should be more ambitious. Be creative, and choose something that interests you!

Your project can be a purely analog system, a digital signal processing system, or a combination of analog and digital. The dSPACE units are available to facilitate real-time implementation of your project. The dSPACE units contain four channels each of A/D and D/A, along with a digital signal processing chip. Alternatively, if your project is not amenable to real-time implementation, then you might perform your processing "off-line" with Matlab and Simulink. In this case the dSPACE units can be used to digitize signals (speech, music, etc.) and transfer the data to the Suns for subsequent analysis with Matlab.

It is also possible for your project to be more of a research paper than an implementation. However, if you choose this type of topic, I would like you to try to implement (or simulate in MATLAB) some aspect of the topic.

Digital filtering is one application of digital signal processing. A digital filter has a similar objective as an analog filter, namely to accentuate certain frequencies while attenuating other frequencies. The digital filter is actually a computer program that processes the sampled data. The dSPACE digital signal processors allow you to implement systems of this type. A digital filter system also requires analog filters to eliminate "aliasing" due to sampling, so you may need to design analog filters to interface with the dSPACE box.

Some Project Ideas

• Analog communication system to transfer analog signals such as speech and music. The system can be implemented with analog components, or the modulation/demodulation can be performed digitally with dSPACE. We will discuss amplitude modulation (AM) in class next week, so you will get an understanding of how this works.
• Digital communication system to transfer bits (0's and 1's). Implement the system in real-time using dSPACE. This project can be somewhat of an extension of the matched filtering Lab 4 we did earlier in the semester, in which you design a system for a real communication channel. You might try building a "modem" that transmits bits over a real telephone line.
• Digital speech processing. An example project is to recognize speech and build a device that turns a motor or a light ON and OFF based on voice commands.
• Audio signal processing. Examples include a digital equalizer system, and special effects such as delays, echos, and reverberation. You might also design and build an analog equalizer.
• Telephone touch-tone dialing: generation and detection of DTMF tones (the ones you hear when you dial a phone). Try to dial an actual phone, and detect the tones from an actual phone in real-time. Investigate alternative approaches to identifying the frequencies that can be more efficient than band-pass filters. (I can provide you with an article describing a new method for DTMF tone detection that you might try to implement.)
• Spectral analysis with the fast Fourier transform (FFT). Interesting projects can be considered to detect signals that are buried in noise, or to remove interference signals.
• Time-domain system identification of RC circuit parameters. We have developed an algorithm that determines the time constant of a first-order system from experimental measurements. The algorithm is "recursive", in that it begins with an initial estimate, and then updates that estimate with each new measured data point. For more information, see
  http://www.eg.bucknell.edu/~eg100ee1/paramest/final.html
• Encryption/decryption (or scrambling/unscrambling) of speech signals to provide security.
• Digital sonar to locate objects with sound waves.
• Digital synthesis of acoustic guitar and other musical instruments.
• Digital image processing, including image deblurring, noise removal, etc.
• An adaptive notch filter to remove sinusoidal interference from a signal. The filter automatically adjusts itself if the frequency of the interference changes.
• Any application of analog and/or digital filters.