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Topic: bandpass filter
Replies: 3   Last Post: Jan 30, 2010 9:18 AM

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Minimax

Posts: 12
Registered: 1/23/09
Re: bandpass filter
Posted: Jan 30, 2010 9:18 AM
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Rune Allnor <allnor@tele.ntnu.no> wrote in message <d4498782-cd40-4f3d-9112-3edfe4fd9e4a@l30g2000yqb.googlegroups.com>...
> On 30 Jan, 13:00, "Minimax " <as...@mail.ru> wrote:
> > Hello!
> > I have 3d series of z500[lat,lon,t],
> > where
> >
> > lat=1:63 (latitude)
> > lon=1:144 (longitude)
> > t=1:1464 (time with 6 hours timestep)
> > 1 day==4 timesteps
> >
> > And I want to do a bandpass filter from 1 to 5 days.
> > I use the code:
> >
> > [b,a] = butter(1,[ 1/(5*4) 1/(1*4) ],'stop');
> > y=filter(b,a,z500);
> >
> > Is this correct code?

>
> No.
>
> First of all, Butterworth filters are based on a number of
> assumptions about the data that (lat,long) data don't meet.
> So you shouldn't use the filter to filter poristional data.
>
> Second, what you want to do is not filtering but resampling.
>
> Rune


Thank you for your help!

What Can i do for filter my data?



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