Lecture Notes for Com Sci 295, Digital Sound Modelling

Department of Computer Science
The University of Chicago

Last modified: Thu Apr 20 15:25:27 CDT 2000

• The lecture notes in LaTeX source, DVI, and PostScript forms.
• Figures in encapsulated PostScript form
  • Ideal spring resonator
  • Qualitative states of spring
  • State and change vectors for vibrating spring
  • Spring system vs. rotor
  • Rotor state parameters x and y as functions of time t
  • Rotor parameters x and y vs. t as a helix in three dimensions
  • Adding two complex numbers
  • The conjugate of a complex number
  • Complex number: Cartesian and polar coordinates
  • Decaying helix
  • Increasing frequency helix
  • Sum of 4 helixes
• Supporting demonstrations in Scilab source form. To run the demos:
  1. If you are in the class at U. Chicago, go to the <scilab_demo> directory that I have already created as ~odonnell/CS295/Scilab, and skip to step 4. If you are not in the class, continue with step 2.
  2. Install Scilab (it's free GPL software).
  3. Download all of the following files into a <scilab_demo> directory. Make sure to give each file precisely the name specified below. Alternative: Download the tarball scilab_demos.tar (112,640 bytes), and unpack it with the command tar -xf scilab_demos.tar.
     • lecture_demos.dem
     • chapter_1_demos.dem
     • chapter_2_demos.dem
     • chapter_3_demos.dem
     • chapter_4_demos.dem
     • chapter_7_demos.dem
     • stretched_scale_demo.dem
     • alias_demos.dem
     • roundoff_demos.dem
     • convolution_demos.dem
     • resonance_demos.dem
     • demo_functions.sci
     • alias_demo.sci
     • helix_demo.sci
     • rotor_demo.sci
     • stretched_scale_demo.sci
     • alias_demo.sci
     • roundoff_demo.sci
     • fourier_demo.sci
     • convolution_demo.sci
     • resonance_demo.sci
     • time-freq.sci
  4. Execute the command scilab in the <scilab_demo> directory.
  5. Give the command exec('lecture_demos.dem') in the Scilab window.
  6. Follow the instructions in the popup windows to navigate and execute the demos.
• Supporting demonstrations in Matlab source form. Matlab is proprietary and expensive. These demonstrations can be converted reasonably easily to Octave, with a bit more work to Scilab, but I haven't had time for that. To run the demos:
  1. Log on to a machine that has Matlab installed (e.g., Classes), and create a <matlab_demo> directory.
  2. Download the tarball filterdemo.tar (40,960 bytes), and unpack it with the command tar -xf filterdemo.tar.
  3. Execute the command matlab in the <matlab_demo> directory.
  4. Give the command filterdemo at the Matlab prompt.
  5. Read the text as it scrolls by. Press the space bar to go on when the demo pauses.
  6. If your particular Matlab is not configured to play sound directly, all of the splay commands will fail. You can download and unpack the tarball filter_sounds.tar.gz (22,520,118 byes), and play the sounds with another application. The unpacking command is tar -xzf filter_sounds.tar.gz. The sounds are in aiff format, but you can easily convert them to other formats with sox.
• You may execute the interactive demos that I showed in class on your own. If you are on one of the CS Department's Linux machines, just set your PATH variable to include ~odonnell/bin.Linux. Then, you may execute click, stretch, and other demos as Ilia Bisnovatyi and I produce them. You may get the source code files to compile the demos on other systems.
• Direct access to the instructor's files.
• Demonstrations from The Johns Hopkins University

odonnell@cs.uchicago.edu