Re: [ferret_users] LSL_Lowpass filter

To: Edward Cokelet - NOAA Federal <edward.d.cokelet@xxxxxxxx>

Subject: Re: [ferret_users] LSL_Lowpass filter

From: saurabh rathore <rohitsrb2020@xxxxxxxxx>

Date: Fri, 8 Apr 2016 13:41:02 +0530

Cc: ferret users <ferret_users@xxxxxxxx>

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from the above two replies and previous links i tried function L=@SPZ:85 (12*7=84 but spz works for odd number) and the results are more or less similar. here red line is for L=@spz:85 and black line is the LSL_Lowpass( A, 84, 85).

regards

On Thu, Apr 7, 2016 at 11:55 PM, Edward Cokelet - NOAA Federal <edward.d.cokelet@xxxxxxxx> wrote:

If you search on “frequency response” in the ferret e-mail archives (http://ferret.pmel.noaa.gov/static/Ferret_search/ferret_mail_archives.html), you’ll find a contribution from me
(http://www.pmel.noaa.gov/maillists/tmap/ferret_users/fu_2015/msg00055.html) on 17 Feb 2015 about a ferret script that gives an example of the frequency response of the LSL_Lowpass filter. As Billy Kessler pointed out, you will always lose some points off both ends of the filtered data. If the filter is symmetric and 2N+1 points wide, then the filtered data will have missing values at the first and last N points.

I attach a slightly clearer version of that LSL Lowpass frequency response script here:

------------------------------------------------------------------------------------------
Edward D. (Ned) Cokelet, Ph.D. Oceanographer
NOAA/PMEL off: (206) 526-6820
7600 Sand Point Way NE fax: (206) 526-6485
Seattle, WA 98115-6349

Edward.D.Cokelet@xxxxxxxx

The contents of this message are mine personally and do not necessarily reflect any position of the Government or the National Oceanic and Atmospheric Administration.

REGARDS

Saurabh Rathore

M.Tech (Earth System Sciences & Technology)

Centre For Oceans, Rivers, Atmosphere & Land Science Technology

Indian Institute Of Technology, Kharagpur

contact :- 91- 8345984434

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