FFT \ Peak points

Question

LALE ASIK 2018-3-9

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/387216-fft-peak-points

编辑： LALE ASIK 2018-4-7

采纳的回答： Akira Agata

在 MATLAB Online 中打开

I am trying to find peak points of Fast Fourier transform (FFT). The graph looks like this:

Could you please help me to fix it?

% amplitude peaks
    pks= findpeaks(mx(1:nfft/2));
    n=min(n,length(pks));
    pks_sort=sort(pks,'descend');%vector of spikes
    for k = 1:n
        locs=find(mx(1:nfft/2)==pks_sort(k));
        f(k)=f_Axis(locs);
    end

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Answer 1

Akira Agata 2018-3-9

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/387216-fft-peak-points#answer_309161

在 MATLAB Online 中打开

Please change the 'amplitude peaks' section of your code to the following:

% amplitude peaks
[pks,locs] = findpeaks(mx(1:nfft/2),'SortStr','descend');
n = min(n,length(pks));
subplot(2,1,2);
plot(f_fft,mx)
hold on
plot(f_fft(locs(1:n)),pks(1:n),'rv','MarkerFaceColor','r')
xlabel('Frequency ')
ylabel(' Amplitutde')