Signal filtering and FFT are the two most used techniques in data processing, especially for engineering experiments. For me I played with these two for lots of times for my own tests. Here, as a demonstration, I provide a piece of Matlab code to implement a lower pass filter and FFT on a sample data.

The sample data is borrowed from a real world vibration test and the data is stored as a Microsoft Excel file. The Matlab script, RunFilterData.m, reads in the file then performs filter and FFT operations on the specified column in the xlsx file. The user can open and check the comments in RunFilterData.m and see what happens inside this demonstration.

All the files used could be obtained here.

The following are the results of the code.

  • The time history. Time domain. ↓

<img>The time history of the data.

  • The results of FFT. Frequency domain. ↓

<img>The time history of the data.