Averaging data to a time base

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Wed, 03/18/2009 - 12:47 pm

Hello. I am new to igor and i am having trouble trying to do the following using the help menus.

I will try to explain my problem as best as i can.

I have a high frequency data column (y) and a time stamp associated with this column (x). The frequency of the data is 6 minutes. What i want to do is to create a new wave with hourly timestamps and average the high frequency data (y) to these new time stamps specifying the range.

eg. If i have a timestamp of 12/03/2009 01:00, then i want to average the high frequency data +/- 30 minutes of the low frequency time stamp and create a new wave.

Cheers
We call that "decimation". Add this line:

#include <Decimation>

to your Procedure window, then close the Procedure window. It will load in a WaveMetrics procedure file that will do the decimation for you. If you the go to the Analysis menu you will find a new item, "Decimate".

You will have to decimate the Y wave and the time wave separately. Be careful that you use the same settings for both.

John Weeks
WaveMetrics, Inc.
support@wavemetrics.com

March 19, 2009 at 05:48 pm - Permalink

Many thanks for your help.

I was wondering if it is also possible to output the standard deviation instead of the average using this technique.

Cheers

March 20, 2009 at 05:53 am - Permalink

gfors wrote:
I was wondering if it is also possible to output the standard deviation instead of the average using this technique.


It looks like you can generate std dev in addition to average. When I #include the decimation procedure file and choose Analysis->Decimation, I see a "Generate a Standard Deviation Wave" popup menu at the bottom of the dialog.

March 20, 2009 at 11:18 pm - Permalink