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Suppose that we have some sample:

y =

   31.2241
   -5.9830
   22.6058
   -2.2309
  -42.8272
   29.2850
   -6.2652
   20.8502
   -2.4639
  -44.7525
   30.1104
   -6.0180
   21.4476
   -1.5089
  -45.1826
   29.2744

and somehow I know that it is obtained via a sinusoidal method which contains two sine functions at different frequencies and amplitudes, so I apply the music method:

pmusic(y,4)

and obtain the plot:

enter image description here

I know the location of peaks at the normalized peaks, but I don't know the actual frequency. How can I find it?

I know the formula is $\frac{\text{normalized frequency}*f_s}{2}$, but what about $f_s$? Can I find it?

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1 Answer 1

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[Y,FS,NBITS]=wavread(FILE) returns the sample rate (FS) in Hz and the number of bits per sample (NBITS) used to encode the data in the music file.

After that, [S,F] = pmusic(Y,4,F,FS) to compute the pseudospectrum at frequencies F in Hz.

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  • $\begingroup$ but what is file?and what is inside it? $\endgroup$
    – user350
    Feb 16, 2014 at 16:42
  • $\begingroup$ actualy i want to find frequency,not indicate myself $\endgroup$
    – user350
    Feb 16, 2014 at 16:43
  • $\begingroup$ how do you get the original data y? You cannot get any information directly from an arbitrary given vector. I thought you sampled the data from a music file or something. $\endgroup$
    – lennon310
    Feb 16, 2014 at 16:45
  • $\begingroup$ no i have some date,which is given at some frequency,but in real live should i know sampled frequency? $\endgroup$
    – user350
    Feb 16, 2014 at 16:54
  • $\begingroup$ suppose that that is signal coming from somewhere with additive noise,then what should i do? $\endgroup$
    – user350
    Feb 16, 2014 at 16:58

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