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--- vpde_lecture34 [2020/04/21 08:38]
trinh created
+++ vpde_lecture34 [2020/04/21 08:42]
trinh
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 The last thing I want to show you today is how a computer stores the information of a signal in terms of a Fourier series. Rather than store information about sines and cosines separately, it is more compact to work with complex-valued functions and store the information together.
+Matlab uses the fft command to calculate the Fourier series of a signal (technically the discrete Fourier transform). I will not explain it in detail at this point. What you have to understand is that you can put a vector into fft, but to plot the Fourier amplitudes, you need to rearrange the output in a funny way.
+<Code:Matlab linenums:1 | Make a sound>
+N = length(f2);
+yhat = fft(f2);
+A = abs(yhat)/N;
+K = (Fs/2)*(1:ceil(N/2))/ceil(N/2);
+A = A(1:ceil(N/2));
+</Code>

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