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please help me extract parts of my data ....

Posted 10 years ago
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I have some data... if i want information for example frequency from this data, What i enter the command?

please reply me...
POSTED BY: Baek Sangin
5 Replies
Posted 10 years ago
thanks! I perfactly forgot the Fourier...
POSTED BY: Baek Sangin
Hi,

If I understand your question correctly, you want to find frequency of a signal/orbit/trajectory from a given sampling, say {{t1,x1},{t2,x2},...,{tn,xn}}?
You need to F1 Fourier[] function and you'll find an example at Applications/Frequency Identification
Please note, that in example given they do not use window function. Also convolution procedure can be made more precise by adding Newton method.
Even without windows and Newton method you can expect to get frequency with accuracy ~ 10^-7, with all additional staff ~ 10^-9.
You might consider searching the web for Laskar's NAFF algorithm.

I.M.
POSTED BY: Ivan Morozov
Thanks for writing us. There are many different kinds of data that could be input and different kinds of frequencies represented by the data. For this reason, it's very hard to answer the question without a more specific example of what you'd like to do. Do you have a simple example of the kind of problem you are interested in solving?
POSTED BY: Sean Clarke
Posted 10 years ago
for example .. data looks like Sin or Cos motion ... than how i looking for frequency of this data??
POSTED BY: Baek Sangin
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