DIGITAL SIGNAL PROCESSING

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Matlab 'diaries'

The following scripts and functions relate to the demonstrations I give in class. They are all contained in the matlab subdirectory of the web site.

Note: The matlab functions defined in the textbook can be downloaded from the publisher's Digital Signal Processing textbook website.

• 2008-09-02: Timescale modification, exponential sequences, 3D visualization of complex numbers.
  Also: solafs the timescale modification program, and stemz, the function to plot complex sequences in 3-D.
• 2008-09-09: Running a system; convolution; using a recorded impulse response to simulate reverberation (sound examples are in the matlab directory).
• 2008-09-16: Solving difference equations algorithmically; cross-correlation visualization (here is corrviz.m).
• 2008-09-18: buildsq.m: Animation to show square wave being built up out of successive terms of Fourier series. Try "buildsq(10)" to start; larger arguments make the fade-in slower.
• 2008-09-23: Convolution in the DTFT domain.
• 2008-09-30: Visualization of the z-transform-magnitude surface.
• 2008-10-07: Illustrating how the effect of a given system on a mixture of two sinusoids is predicted by the frequency response.
• 2008-10-09: Hand-designed filter to remove 0.4 rad/samp sinusoid while preserving 0.1 rad/samp sine, and the script I used to generate movies illustrating the geometric interpretation of pole-zero diagrams (relies on Malcolm Slaney's MakeQTMovie.m).
• 2008-10-14: Here's an excellent interactive pole-zero editor from Jim McClellan at Georgia Tech. You can drag poles and zeros around the z-plane, and immediately see how the magnitude and phase response, as well as the impulse response, change. Here's a local copy of the documentation.
• 2008-10-14: Illustration of the 'sound' of group delay, and the phasegroupdelay function to visualize the difference between delaying the envelope (group delay) and delaying the carrier (phase delay)
• 2008-10-16: Simple bandpass filter example.
• 2008-10-28: Allpass filters.
• 2008-11-06: Analog Butterworth filter design.
• 2008-11-13: FIR filter design by windowing ideal IR.
• 2008-11-18: The animation to illustrate the Remez exchange algorithm is remezviz (no arguments) and it calls lagrangepoly to find the polynomial that fits the control points.
• 2008-11-20: FFT and STFT examples.
• 2008-11-25: Aliasing and resampling.

Dan Ellis <dpwe@ee.columbia.edu>
Last updated: Tue Nov 25 10:18:26 EST 2008