Rectangular mask short-time Fourier transform

In mathematics and Fourier analysis, a rectangular mask short-time Fourier transform (rec-STFT) has the simple form of short-time Fourier transform.

Other types of the STFT may require more computation time than the rec-STFT.

The rectangular mask function can be defined for some bound (B) over time (t) as We can change B for different tradeoffs between desired time resolution and frequency resolution.

Rec-STFT Inverse form Rec-STFT has similar properties with Fourier transform (a) (b) If

are their rec-STFTs, then From the image, when B is smaller, the time resolution is better.

B = 50, x -axis (sec)
Spectrograms produced from applying a rec-STFT on a function consisting of 3 consecutive cosine waves. (top spectrogram uses smaller B of 0.5, middle uses B of 1, and bottom uses larger B of 2.)