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Perform convolution of the fitting function with the instrument response while performing the fitting.

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The App lets you perform convolution of a fitting function with the instrument response while performing the fitting.


Download the file Fit Convolution.opx, and then drag-and-drop onto the Origin workspace. An icon will appear in the Apps Gallery window.


  1. Active a worksheet with the first 3 columns containing numeric data.
    1st Column: Sampling
    2nd Column: Signal
    3rd Column: Impulse Response
  2. Launch this app by clicking on its icon.
  3. Define the signal function f(x).
    f(x) should not include the y offset parameter y0. Turn on Include y Offset Parameter y0 if necessary.
    For example, set the input type as Simple and the f(x) defined as A * exp(-t * x)
    You can save the fitting function as FDF in Convolution category by clicking the Save as... button then you can re-use it later
    1) in Origin's built-in tool Nonlinear Curve Fit, or
    2) in this app by clicking the link in the Signal Function area. The link is available only if the text area is empty. It brings up a select box (if there's any), where you can click OK to confirm the selection or click anywhere outside the box to cancel it.
    Default the signal function is defined as Origin C expression. You can change the Expression Type accordingly to support LabTalk expression.
  4. Set proper initial values to the parameters and click 1 Iter. to perform fitting once or Fit directly.
  5. Click the Report button to generate a report.

Sample OPJU File
This app provides a sample OPJU file. Right click on the Fit Convolution icon in the Apps Gallery window, and choose Show Samples Folder from the short-cut menu. A folder will open. Drag-and-drop the project file FitConvEx.opju from the folder onto Origin. The Notes window in the project shows detailed steps including how to use options X Shift and XYXY for Input Type.
Note: If you wish to save the OPJU after changing, it is recommended that you save to a different folder location (e.g. User Files Folder).


v1.2: data shift.
v1.1: Support LabTalk expression.

Reviews and Comments:
08/18/2023OriginLabHi vadimtrepalin94,
Thanks for your suggestion. We will improve this app to support to fit the plot on future version.
OriginLab Tech Support

08/17/2023vadimtrepalin94Useful app. Some difficulties with using it still present though. For example, fit depends heavily on the initial guess, especially with multiple parameters in the signal function. Therefore, I should be able to test "goodness" of initial guess visually, but the app does not allow to do it properly. My data is usually plotted on a log scale and I may want to zoom into a region of interest. But the app automatically plots it in linear scale and works only with workbooks, thus you cannot create your own graph the way you like it and then run app. So this would be a great improvement for the app.

01/26/2022buckupDoes not work. It chrashes on 2020b (Academic) with script error.


03/03/2019lsisome customers need this in Japan.