The STFT as a Time-Frequency Distribution

The Short Time Fourier Transform (STFT) at frame $m$ is usually defined as $X_m(\omega_k)$ , the sampled DTFT of the $m$ th data frame $x_m(n) = x(n)w(n-mR)$ . It is a function of both time (frame number $m$ ) and frequency ( $\omega_k = 2\pi k/N$ ). The STFT is just one example of a time-frequency distribution. Others include

• Constant-Q STFTs [27]
• Dyadic Wavelet Filterbank [249]
• Wigner Distribution [36]