To find the frequency components in the data and make a frequency plot

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aneps 2018-1-4

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https://ww2.mathworks.cn/matlabcentral/answers/375516-to-find-the-frequency-components-in-the-data-and-make-a-frequency-plot

评论： aneps 2018-1-5

Test_Sample.txt

I have a data which is a frequency modulated signal. I want to make a matlab code to find the frequency components in it using Fourier transform method and make a frequency plot? I tried fft(data(:,2)) but most of the time it is giving me wrong answers. I am attaching the data. The first column is time and the second column is the signal.

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采纳的回答

Birdman 2018-1-4

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https://ww2.mathworks.cn/matlabcentral/answers/375516-to-find-the-frequency-components-in-the-data-and-make-a-frequency-plot#answer_298642

在 MATLAB Online 中打开

Test_Sample_edited.txt

Use the attached file with the following code:

filename='Test_Sample_edited.txt';
A=load(filename);
time=A(:,1);
signal=A(:,2);
h1=spectrum.welch;
set(h1,'Windowname','Hann');
Fs=1000;
set(h1,'OverlapPercent',66.7);
set(h1,'SegmentLength',2048);
myPsd=psd(h1,A(:,2)-mean(A(:,2)),'Fs',Fs)
semilogx(myPsd.Frequencies,myPsd.Data);xlabel('Frequency(rad/sec)');