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Topic: How to make this bandpass filter?
Replies: 5   Last Post: Feb 1, 2010 12:33 PM

 Messages: [ Previous | Next ]
 Minimax Posts: 12 Registered: 1/23/09
Re: How to make this bandpass filter?
Posted: Jan 31, 2010 8:25 AM

"Wayne King" <wmkingty@gmail.com> wrote in message <hk3tui\$mf6\$1@fred.mathworks.com>...
> "Minimax " <aseid@mail.ru> wrote in message <hk3j5m\$j0k\$1@fred.mathworks.com>...
> > Good day!
> > I have the 3d matrix z500(latitude,longitude,time),
> > where
> > latitue=1:73
> > longitude=1:144
> > time=1:124 (here 31 days, because 4 timestep is 1 day)
> >
> > I need a bandpass filter that passes days from 1 to 5.
> >
> > How to make this bandpass filter?

> Hi, what makes you think you need a "bandpass filter" for this problem. Can you be more specific about what you're doing? To understand, you have a 73X144X124 matrix and you just want to extract the data corresponding to days 1 to 5? If that is the case and your data is Z, why can't you just do:
>
> NewData = Z(:,:,1:20);
>
> Wayne

Yes, i have a 73X144X124 matrix and i want to apply for my data a bandpass filter
like below, but someone said that this code was incorrect.
i need it for get the filtered field of Z with periods (1<=T<=5 days).

[b,a] = butter(1,[ 1/(5*4) 1/(1*4) ],'stop');
y=filter(b,a,z500);

Date Subject Author
1/31/10 Minimax
1/31/10 Wayne King
1/31/10 Minimax
1/31/10 Wayne King
2/1/10 Minimax
2/1/10 Wayne King