Multi-Resolution Spectral Analysis of Vowels in Tunisian Context

Classic speech spectrogram shows log-magnitude amplitude (dB) versus time and frequency. The sound pressure level in dB is approximately proportional to the volume perceived by the ear. The classic speech sonagram offers a single integration time which is the length of the window. It implements a uniform bandpass filter, the spectral samples are regularly spaced and correspond to equal bandwidths. The choice of the window length determines the time-frequency resolution for all frequencies of sonagram. The more the window is narrower, the better the time resolution and the worse the frequency resolution. This implies that the display resolution of formants, voicing and frictions at low frequencies is less good than the resolution of the bursts in the high frequencies and vice versa. It is so necessary to make the right choice of windows compared to the signal.