Hanning window And DFT Exercise

Construct a Matlab function in the file “wft.m” that will select a section from a file and window it. The function “wft” is to be called as follows:

y = wft(s, t, n);

where s is the signal, t is the time in the middle of the window, and n is a window length.

You might use the following steps:

1) Select the desired section from the signal, for example using

s(floor(t-n/2)+(1:n));

(if you don’t see how this works, try “help colon”).

2) Multiply elementwise with a Hanning window of length n, using “.*”

3) Use the built-in Matlab fft function to calculate the DFT.

Use window lengths of 54, 256 and 1024.

Use times of 10000, 60000 and 110000 for the window position.