S522, Kewley-Port
Spring, 2008

Assignment #12 (short!)

DFT Week 12, due 4/9/08

A) Load from Oncourse, m-code-dkp

  1. obtain s522dft.zip and unzip
  2. Extract dfs.m and ee220.wav (vowel /i/, F0 = 220 Hz, Fs=10000 Hz) [other code might be of interest]

B) Read ee220.wav into Matlab.

C) Extract one pitch pulse of n = 46 long for /i/,
xn = x(581:581+n-1);

D) Edit out a piece of the vowel of 512 points in length:
x512 = x(581:581+511)

E) Calculate the magnitude spectrum for the following. In some cases the stem plot may be more useful than the 'plot' command. Print out each magnitude spectrum, and on the print out indicate the exact command(s) you used in Matlab to generate the plots. In a short summary, comment on how the four DFT's are related.

  1. DFT of one pitch pulse, xn, using dfs.m
  2. DFT of one pitch pulse, xn, using fft.m
  3. DFT of 512, x512, using fft.m.
  4. DFT of one pitch pulse, xn, padded with 512-46 zeros.

F) On a print out of dfs.m, briefly explain what the last 4 lines of code are doing.

{Updated on 3/26/08}