The App lets you perform convolution of a fitting function with the instrument response while performing the fitting.
Installation
Download the file Fit Convolution.opx, and then drag-and-drop onto the Origin workspace. An icon will appear in the Apps Gallery window.
Operation
- Active a worksheet with the first 3 columns containing numeric data.
1st Column: Sampling
2nd Column: Signal
3rd Column: Impulse Response
- Launch this app by clicking on its icon.
- 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.
- Set proper initial values to the parameters and click 1 Iter. to perform fitting once or Fit directly.
- 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).