The Origin Forum
File Exchange
Try Origin for Free
The Origin Forum
Home | Profile | Register | Active Topics | Members | Search | FAQ | Send File to Tech support
Username:
 Password:
Save Password
Forgot your Password? | Admin Options

 All Forums
 Origin Forum
 Origin Forum
 Convolution fitting		  New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic Lock Topic Edit Topic Delete Topic New Topic Reply to Topic

yeyongfeng

China
4 Posts
Posted - 01/02/2024 :  04:25:55 AM  Show Profile  Edit Topic  Reply with Quote  View user's IP address  Delete Topic
Origin Ver. and Service Release (Select Help-->About Origin): Originpro 2021
Operating System:windows 10

Hello,
I want to fit a such a function convoluted by 2 functions. This function contains a delta function δ(x)=1 when x=0 or δ(x)=0 when x≠0. I have no idea about how to construct such a function in NLFit tool.

yeyongfeng

China
4 Posts
Posted - 01/02/2024 :  04:31:44 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
I uploaded a image to show this function. Did I make it? Why can't I see it here?
Go to Top of Page

yeyongfeng

China
4 Posts
Posted - 01/02/2024 :  04:37:27 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
S(x)=R(x)⨂[A0·δ(x)+A1·f(x)]+A2, I typed it. I have S(x) and R(x) now, and want to fit A0 to A2. f(x) is a lorentzian function.
Go to Top of Page

snowli

USA
1379 Posts
Posted - 01/02/2024 :  11:41:07 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Please check if this app helps
https://www.originlab.com/fileExchange/details.aspx?fid=423

We also have a blog on Fit Convolution
https://blog.originlab.com/fit-convolution

Thanks, Snow
Go to Top of Page

yeyongfeng

China
4 Posts
Posted - 01/03/2024 :  01:06:41 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Much thanks for responses. The App FitConvolution seems help. But the question is that the App requires a analytical signal function or original function. How could I express the piecewise function i.e. the delta function?
Go to Top of Page

YimingChen

1594 Posts
Posted - 01/03/2024 :  09:40:56 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
The app is to fit the convolution of a function and a response signal. In your case, you need to create a fitting function with the convolution of two functions. So you need to define a function with integral. Please refer to this tutorial page.
https://www.originlab.com/doc/en/Tutorials/Fitting-Integral-LabTalk

for the delta function, you can use
if(x=0, 1, 0)


Thank you
James
Go to Top of Page
  Previous Topic Topic Next Topic Lock Topic Edit Topic Delete Topic New Topic Reply to Topic
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
The Origin Forum © 2020 Originlab Corporation Go To Top Of Page
Snitz Forums 2000