comp.lang.idl-pvwave archive: archive » Re: question relating to FFT

Home » Public Forums » archive » Re: question relating to FFT

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: question relating to FFT [message #65373 is a reply to message #65372]

Mon, 02 March 2009 14:03

Hu
Messages: 35
Registered: January 2009

Member

On Mar 2, 2:37 pm, Paolo <pgri...@gmail.com> wrote:
> Hu wrote:
>> Hi, there
>> I try to use FFT function to smooth a curve (an array), and the code
>> is like this:
>
>> FUNCTION FOURIER,ARRAY ;*****FAST FOURIER FLITER
>> FILTER=1.0/(1.0+DIST(152)/4.0)^2
>> newARRAY=FFT(FFT(ARRAY,-1)*FILTER,1)
>> RETURN,newARRAY
>> END
>
>> when I got an array X (has 152 elements) and use this function like :
>
>> Y = FOURIER(X)
>
>> I got an result Y with 152 elements, but all the elements are complex
>> number, but How can I got an array filled with regular number, not
>> complex number?
>
> To get real number,
> you can take the REAL_PART or the ABS of your array.
> But you are using a very strange filter indeed...
>
> Ciao,
> Paolo
>
>
>
>> I mean, I want to use the result to calculate regression relationship
>> with other array.
>
>
Thank you ,and Why do you say it's strange? I want to denoise the
whole curve( store as array) to make it more reasonable.

Report message to a moderator

[Message index]

		Re: question relating to FFT By: David Fanning on Mon, 02 March 2009 15:30
		Re: question relating to FFT By: pgrigis on Mon, 02 March 2009 15:21
		Re: question relating to FFT By: Hu on Mon, 02 March 2009 14:03
		Re: question relating to FFT By: pgrigis on Mon, 02 March 2009 11:37
		Re: question relating to FFT By: pgrigis on Tue, 03 March 2009 08:14

Previous Topic:	crazy question
Next Topic:	Hide functions from other procedures

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Sun Oct 12 12:17:54 PDT 2025

Total time taken to generate the page: 2.23647 seconds