Best method to reduce high frequency data

[Julia Dawkins]

Hi,

I am receiving data recorded at approximately 5 Hz.  In DIAdem I would like to calculate a "1 Hz mean" of my 5 Hz data, so that one point *in the new channel) would represent the average of the last 5 points (from the original channel).  Is there an already-defined function in ANALYSIS that could help me do this?  I have tried a few different functions, but am not sure exactly how they work, and would prefer not to write a script to make this calculation. 

Thanks!

Julia Moeller

[RMOZARD]

Hi Julia,

I am afraid I can partly help you. To reduce the frequency from 5 Hz to e.g.: 1 Hz you can use the function "File>>>paste from file", then select the file and after "Reduce lines >>>line reduc..." . You could set the line interval width for each 5 lines, so the data will be reduced.

Hope it helps a little bit.

Rodrigo (Brazil) 🙂

[Ralf_Mueller]

Hi Julia,

Please use the Reducing Classification in the Statistics function bar. Provide one x- and one y-channel and select Mean as reduction mode. In the classes dialog box keep the default settings and insert "Channellength/5" as No. of classes.

Regards,
Ralf

[Julia Dawkins]

That's great, thank you Ralf

[Normann]

i also need to reduce my data of a certain group and found this thread. i tried to type "Channellength/5" as No. of classes but i get an error message "cannot assign Channellength/5 to the integer variable   Assignment:< CLASSNO=Channellength/5>

what do i have to type to get every 10. value respectively the mean value of 10 values.

if i tpe 5 as No. of classes my channel length is only 5. mi channel length is 18000, if i type 1800 as no of classes will i get the mean value of 10 following values?

[Brad_Turpin]

Hi All,

Normann and I figured things out via email, but for anyone else searching for this thread, what I suggested to him was that

the easiest way to average together each window of 5 values to resample each signal is to load the data set with data reduction. Instead of dragging the data file into the Data Portal, right-click on it and select the "Data Reduction..." context menu, then select the data reduction parameters you want... in this case to calculate the mean from each window of 5 points.

Brad Turpin

DIAdem Product Support Engineer

National Instruments

[nickom]

Hello Brad,

I realise this topic is a little old but i'm hoping you can help.

• I have a number of channels from a TDMS file that is continully being added to from a labview VI,  
• periodically I run a script in Diadem to reload all the data and perform analysis and reporting,  
• each of the channels are written at 1 per second,
• I would like to take this data and average 60 records per minute
• so rather than 3600 records per channel for each hour, i would have an average of records spilt up to 60,  1 minute records
• then i will create a seperate channel that is 1 minute average of the last 60 records

 looking at the solution above i am wondering how this could be scripted.

Hope you can help and thanks in advance

Nick

[Pesmith8]

Nick

The script example to do a reduced data load is :

Dim oMyElementList
Set oMyElementList = DataFileLoadRed("Example.tdm","TDM","","IntervalWidth",100,eInterMeanValue OR eInterFirstValue)
Call ChnSum(oMyElementList, "ChannelSum")

Look up the help on DataFileLoadRed

Paul

[nickom]

Thanks Paul,

I'll give it a go .

regards

Nick