Short-time Fourier transform for large scale data

A simple version of Short-time Fourier transform 数据处理相关项目合作，长期有效。

The code of Short-time Fourier transform for large scale data is written by Gang Yu.

Data is downloaded from "Antoni J, Griffaton J, André H, et al. Feedback on the Surveillance 8 challenge: Vibration-based diagnosis of a Safran aircraft engine[J]. Mechanical Systems and Signal Processing, 2017, 97: 112-144."

Best thanks to Pro. J. Antoni.

Reference:

[1] Yu G, Yu M, Xu C. Synchroextracting transform[J]. IEEE Transactions on Industrial Electronics, 2017, 64(10): 8042-8054.

[2] Yu G, Wang Z, Zhao P. Multisynchrosqueezing transform[J]. IEEE Transactions on Industrial Electronics, 2018, 66(7): 5441-5455.