[ncl-talk] bandpass filter issue

[Maria Gehne - NOAA Affiliate]

Can you explain in more detail what you are trying to do? Are you trying to
only look at phenomena that have a period of 16 days?

Maria

On Tue, Oct 6, 2015 at 12:31 AM, Xi Chang <xi.chang01 at gmail.com> wrote:

> Thanks for the reply. No i dont use it, since what i need is how to
> extract/filter the daily data having frequency 1/16 day. is it possible to
> only use bandpass filter?
>
>
>
>
> On Tuesday, 6 October 2015, Dennis Shea <shea at ucar.edu> wrote:
>
>> Are you looking a 'complex demodulation" ???
>>
>> If so, that is in the 6.3.1 release:
>>   http://www.ncl.ucar.edu/future_release.shtml
>>
>> Click 'demod_cmplx'  =>
>> http://www.ncl.ucar.edu/Document/Functions/Contributed/demod_cmplx.shtml
>>
>> See Examples at the bottom of
>> http://www.ncl.ucar.edu/Applications/spec.shtml
>>
>>
>> On Mon, Oct 5, 2015 at 4:32 PM, Xi Chang <xi.chang01 at gmail.com> wrote:
>> > Hi NCL,
>> >
>> > I have daily data 10 years. I'd like to filter the data at frequency
>> (1/16)
>> > day. To do so what the most appropiate  frquency ranges that i have to
>> use
>> > ?, is it domething like fa=1/15 and fb=1/17 ?
>> > I aware if the band is too narrow the filtered signals are fake
>> /artificial
>> > (i tesed with ncl butterwooth and the filtered results are weird) ? is
>> there
>> > any idea how to do that appropriately? do i need to use hourly data
>> instead
>> > of daily?
>> >
>> > Thanks
>> >
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>>
>
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