FINDING FREQUENCY AND AMPLITUDE OF A SINUSOID FROM DATA POINTS.

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ARAVINDHAN RAMESH 2014-5-27

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评论： rifat 2014-5-27

Hello,

I have a text file with two columns: One with the time instant and the other with the corresponding velocity of a sound wave at a particular point at that instant. I know that the wave is a sinusoid (After plotting).

How can I find the exact frequency and amplitude of the wave? Is there a function in MATLAB?

Thanks in advance.

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Answer 1

rifat 2014-5-27

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https://ww2.mathworks.cn/matlabcentral/answers/131326-finding-frequency-and-amplitude-of-a-sinusoid-from-data-points#answer_138457

在 MATLAB Online 中打开

len=length(signal);
fs=50 % assuming you know the sampling frequency of your signal
n=0:len-1;
N=n*fs/(len-1); % convert x-axis in actual frequency
y=fft(signal);
plot(N,abs(y));

from the plot you can determine the frequency peak. I do not know any function for amplitude estimation. If the signal relatively low noisy, then (max(signal)-min(signal))/2 should give a rough estimate