Speech spectrograms using the fast Fourier transform
Alan V. Oppenheim · IEEE Spectrum · 1970
An important aid in the analysis and display of speech is the sound spectrogram, which represents a time-frequency-intensity display of the short-time spectrum.1-3With many modern speech facilities centering around small or medium-size computers, it is often useful to generate spectrograms digitally, online. The fast Fourier transform algorithm provides a mechanism for implementing this efficiently.