Lecture 33 Blog, ECE438 Fall 2010, Prof. Boutin
Wednesday November 10, 2010 (Week 12) - See Course Outline.
We began the lecture by discussing how to use formants to recognize voiced phonemes. More specifically, we discussed how phoneme samples (i.e. recordings of different people saying the phoneme in different situations) can be used to define regions in space (for example, a 2D plane) corresponding to different phonemes. It was noted that this is an example of the use of a standard technique from Decision Theory. If you are interested in learning more about Decision theory, you should consider participating in this coming Decision Theory maymester or taking my Decision Theory graduate course.
Many questions were raised regarding the changes induced in the formant frequencies by changes in pitch (e.g., men versus women voices). I would like to encourage each of you to try to experiment with actual voice samples to see what happens. Students sharing their results on Rhea will receive bonus points.
The second part of the lecture was spent talking about the short-time Fourier transform and sound spectograms. The issue of window function length and shapes were discussed, and the uncertainty principle of spectograms was stated.
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