Play Pitch Period Contour

The exercise tries to separate the main properties of speech excitation function from vocal tract.

The goal of this MATLAB Exercise is to try to separate out the main properties (primarily pitch and intensity) of the speech excitation function (as estimated using LPC analysis) from the properties of the vocal tract (primarily the resonance structure associated with the spoken sound). To achieve this goal the proposed MATLAB program, using either a pre-recorded speech .wav file or a newly recorded file (done within this program), estimates the pitch period contour of the speech file and creates a pseudo-excitation function of pitch pulses (separated according to the pitch period estimate) and random noise. The program estimates the pitch period contour of the speech utterance and creates the two-state excitation sequence which is then convolved with the impulse response of a selected vowel sound (any of 10 standard vowels), and the resulting pitch modulated vowel is played out, thereby emphasizing the speech signal rhythm and tone without having the actually spoken sounds reproduced. In a sense, this program plays a speech melody (as obtained from the pitch period contour) without preserving the intelligibility of the spoken input utterance.