What is stft

1. What is the meaning of STFT?
2. Why is STFT used?
3. What is the difference between FFT and STFT?
4. How is STFT determined?
5. What is the magnitude of STFT?
6. What is the difference between STFT and wavelet transform?

What is the meaning of STFT?

Short-time Fourier transform (STFT) is a sequence of Fourier transforms of a windowed signal.

Why is STFT used?

The short-time Fourier transform (STFT) is used to analyze how the frequency content of a nonstationary signal changes over time. The magnitude squared of the STFT is known as the spectrogram time-frequency representation of the signal.

What is the difference between FFT and STFT?

FFT has a resolution of 2048 lines, Blackman window, and 50% overlap and STFT also has Block size 2048, FFT size 16K, Blackman window used, and 50% overlap. As we can see, STFT performs better with the same block size (but more calculated lines). We improved frequency resolution for the same amount of scooped data.

How is STFT determined?

In practice, the procedure for computing STFTs is to divide a longer time signal into shorter segments of equal length and then compute the Fourier transform separately on each shorter segment. This reveals the Fourier spectrum on each shorter segment.

What is the magnitude of STFT?

STFT magnitude, specified as a matrix. s must correspond to a single-channel, real-valued signal. Example: abs ( stft ( sin (pi/2*(0:255)),'FFTLength',128)) specifies the STFT magnitude of a sinusoid. Example: abs ( stft ( chirp (0:1/1e3:1,25,1,50))) specifies the STFT magnitude of a chirp sampled at 1 kHz.

What is the difference between STFT and wavelet transform?

In contrast to the standard STFT which uses a single window size, the wavelet transform (WT) uses short windows at high frequencies and long windows at low frequencies [21]. Wavelets rely on the use of a mother wavelet function that can be scaled and shifted, to correlate with the anomalies or events of the signals.