Perform short-time Fourier transform with the window size fixed in the frequency domain.

• Purpose
  This app can be used to perform short-time Fourier transform with the window size fixed in the frequency domain, that is to use the concept of the short-time Fourier transform, but fix the window size in the frequency domain instead of in the time domain.
• Features Include:
  • Specify sampling interval or get sampling interval from X automatically.
  • Mutiple types of windows are supported, including Rectangle, Welch, Triangular, Bartlett, Hanning, Hamming, Blackman, Gaussian, Kaiser and Parzen.
  • Estimate the maximum frequency and number of frequencies.
  • Estimate the required number of operations and output matrix size automatically.
  • Multiple threads technology is used for improving the speed.
  • Output both the result data and contour plot.
• Installation
  Download the file "Modified Short-Time Fourier Transform.opx", and then drag-and-drop onto the Origin workspace. An icon will appear in the Apps gallery window.
• Operation
  1. Import desired data into a worksheet.
  2. Select one Y column, abd click the icon in the Apps Gallery panel.
  3. In the pop up dialog, the selected Y column will be as the Input Signal.
  4. If there is X column for the selected Y column, you can use it to calculate the sampling interval, or you can specify sampling interval by yourself.
  5. Choose Number of Cycles by dragging the slider or put the number to the input box.
  6. Choose the Window to use.
  7. The Max Frequency and Number of Frequencies will be calculated automatically, also the needed number of operations and output matrix size.
  8. To preview the contour plot by the current settings, click the Preview button.
  9. Click OK button to create report.
• Dialog Settings
  • Input Signal: Specify the input signal, with related X or not.
  • Specify Sampling Interval: If checked, you can specify the sampling interval by yourself.
  • Sampling Interval: If check Specify Sampling Interval, you can specify the sampling interval here.
  • Number of Cycles: Choose the number of cycles.
  • Window: Choose the window, options include Rectangle, Welch, Triangular, Bartlett, Hanning, Hamming, Blackman, Gaussian, Kaiser and Parzen.
  • Max Frequency: Show the maximum frequency.
  • Number of Frequencies: Show the number of frequencies.
  • Output Worksheet: Specify the output worksheet.
  • Preview: Click this button to preview the contour plot.
  • OK: Click this button to create report.
  • Cancel: Close dialog without doing anything.
• References
  • Carlos Mateo, Juan Antonio Talavera, Short-time Fourier transform with the window size fixed in the frequency domain. Digital Signal Processing, Volume 77, June 2018, Pages 13-21

v1.1 4/25/2023 Updated to make it compatible with Origin 2023b.