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spectral centroid in matlab

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Abhijit Sardar
Abhijit Sardar on 16 Jan 2021
Commented: jibrahim on 19 Jan 2021
i have amplitude data of 1024 microseconds with the sampling the sampling frequency of 1MHz . I am trying to find the spectral cetroid using the function available in the matlab.I am using "spectralCentroid(m,1)" where m is the amplitude data it is giving error"Expected WINDOW to be nonempty" as far as i know f is the sampling freqency in hz i have inputed the sampling frequency as 1000000 Hz but still showing error.Can somebody help me in this?

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Image Analyst
Image Analyst on 16 Jan 2021
Make it easy for us to help you. Please attach your signal.
Abhijit Sardar
Abhijit Sardar on 17 Jan 2021
Hi i am attaching amplitude data for one signal.like this there are 50000 data files. can you tell me how to find the spectral centroid for all the amplitude signal data.

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Answers (1)

jibrahim
jibrahim on 19 Jan 2021
Hi Abhijit,
spectralCentroid uses a window internally to compute the STFT of the signal. The default window length is 30 milliseconds, which is longer than your input signal, which explains the error.
You should set a shorter window, for example:
c = spectralCentroid(x,1e6,'Window',hann(1024),'OverlapLength',512);
Note that spectralCentroid was designed with audio signals in mind, so it might not be suitable for your needs. Consider using the function meanfreq instead.

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Abhijit Sardar
Abhijit Sardar on 19 Jan 2021
actually i wanted to find the value of frequency centroid of gravity(KHz) so i don't know which function would be suitable to find this parameter.I assumed it is similar to spectralcentroid idk if i am correct. for meanfreq do we need to feed the ouput frequency data after doing FFT on the amplitude data.
jibrahim
jibrahim on 19 Jan 2021
I think you should use meanfreq. You do not need to do an FFT before calling meanfreq. Just feed it the time-domain signal.
FREQ = meanfreq(X, Fs)

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