To create Hamming window of length 64 with overlap

问题:

I am trying to give for Wigner-Ville Distribution Hamming Window of length 64 with 60% overlap here. I can create Hamming window of length 64 by

h=hamming(64);

Here is some theoretical pieces of advice about the issue. The window seems to be some sort of convolution of three Hamming waves with 60% probability for convolution.

The overlap seems to be some sort of convolution of three functions. My try for three windows and their overlaps

conv(conv(hamming(64), hamming(64)), conv(hamming(64), hamming(64)))

My try for two windows and their overlaps

h = conv(hamming(64), hamming(64));

Both of the results do not seem to give me any better Wigner-Ville distribution results. Many cloudy peaks are still visible. So the key seems to separate in time the windows, since the current result of the window function returns exactly the same picture as with hamming(64) window only.

Thinking the 60% overlap

The dimensions of hamming(64) are 64x1 double, while of conv(hamming(64), hamming(64)) 127x1 double. To make a probabilistic algorithm of 60% chance is not straightforward, because we cannot iterate both functions linearly.

How can you create hamming window with 60% overlap?

回答1:

A quick search indicated buffer might be worth attempting.

h = hamming(64);
y = buffer(h, 1, floor(64 * 0.6));

But my Matlab version does not support this function, so I didn't try.

回答2:

Based on Floris' comment. Run Wigner-Ville distribution with 60% overlap of Hamming window 64.

h = hamming(64);
h2 = hamming(38);
h = conv(h, h2);
[B,T,F] = tfrwv(data, 1:length(data), length(data), h);

The picture seems to be exactly the same as with hamming-64 window. The picture should not be the same, since the vector hamming-64 and this windowing function differ in values. So probably the norm should be studied to estimate the thing.

The log(abs(data)) gives on the left-hand-side, while the original on the right-hand side

Here now logarithmic function applied to distribution with Hamming 64 and to the other with Hamming 64 but with overlap 60%

The pictures seem to be the same after logaritmic function too.