curve fitting

[yesyes]

Hi All,

I am a newbie in LABVIEW and i have got a set of measurements data points and i would like to use non linear curve fitting for my case.  

I would like to do a curve fitting for the blue measured points, so that they almost align to that of the pink curve. 

The link to my file can be found here. 

http://www.mediafire.com/?sharekey=5a8f6af29da35777d2db6fb9a8902bda

Thanksin advance

yesyes

[yenknip]

So you mean to say your pink line are your data points and your blue line is your best fit curve? And you want to better define your blue line equation.

 

Message Edited by yenknip on 12-03-2008 10:47 AM

[yesyes]

Hi Yenkin,

Thanks for your reply. Actually the bluelines are my online measurement data points. and i wanted to fit these data points which would kind of match the pinkline which is served as reference. 

Thanks

yesyes

[yenknip]

Hah, I knew the blue were data, but somehow the colours swapped over somewhere between my brain and my fingers O_o

Firstly, is this the sort of fitting you are attempting? How are you defining your reference line at the moment?

[yesyes]

HI Ed,

the pink curves are read from the flowmeter thorugh picoscope and with labview. 

Thanks

yesyes

[Coq_Rouge]

I am not sure what you are looking for. Is it curve fitting or filtering? The blue line looks like a noisi version of the pink line. In such case a digital filter may help you out some. A trick I use quite often is downsampling. Say you need sampel rate equal to 50 Hz. In such case i often use a sampel rate equal to 1000Hz. The data presented to the user is an average value of 20 samples. (1000/50=20). I would also inspect the path from your signal source to your Daq card. Noise may me picked up here. Pay atention to every part of the signal chain.  A chain is never stronger than the weakest segment

[yesyes]

Hi Ed,

yes, this is the kind of fit i would like to obtain where i would like to negelect the peaks and obtain a smooth curve, already FFT filter is being implemented into my LABVIEW code.  Could you kindly help me out to do the non-linear curve fitting using Labview.

thanks in advance

yesyes