Prof. Rich Kozick
ELEC 320, Fall 1997
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
First, please finish some items from Lab 4:
- Make sure your Sun accounts are set up to use the dSPACE boxes.
Go through the steps of programming the dSPACE box from Simulink and
from a C program.
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.
Also, modify the C program to add and subtract adjacent samples,
as described on Lab 4.
- Try adding a digital filter block to your Simulink diagram,
and run it on the dSPACE box.
Understand how to set the filter cutoff, and
verify the filtering behavior.
Then, try the "real-time update of parameters", as described on the
dSPACE Instructions page.
- Review the descriptions of some past projects from
the 1994 and 1995
Signals and Systems course described at
- 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.
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
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
Some suggestions for projects are listed below.
Selected projects from 1994 and 1995 are summarized on the Web
You are free (and encouraged!) to pursue a project that
are in-line with your interests!
I will be happy to discuss project ideas with you.
Please work in groups of 1, 2, or 3 students on the project.
- 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
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
Lab 3 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.
- 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
For more information, see
- 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
- Digital image processing, including image deblurring,
noise removal, etc.
- An adaptive notch filter to remove sinusoidal interference from
The filter automatically adjusts itself if the frequency of the
- Any application of analog and/or digital filters.