Linear Predictive Speech Synthesizer

Need help with a matlab work. It involves writing code for a linear predictive speech synthesizer. I'm very new learning matlab/speech processing. Heres what I need to do:

To synthesize some vowels (monophthongs) using the source-filter model of speech production. The formant structure of each vowel will be estimated directly from a real speech sample, using linear predictive coding (LPC). Synthesized vowels can then be generated by passing a periodic impulse train through the all-pole filter obtained.

Download a set of male and female vowel phoneme samples in .wav format from:

http://personal.ee.surrey.ac.uk/Personal/W.Wang/assignment.html

Choose one male vowel and one female vowel from the sample set, and then choose a quasi- stationary segment of around 100ms in length from each vowel for the LPC estimation.

For each of the vowel segments:

Model Estimation

Use one of the Matlab functions for autoregressive (AR) modelling (e.g. lpc, aryule, arcov; the help files should contain details of each method), to estimate the LPC coefficients that provide a least-squares error fit to the speech waveform. Plot the frequency response of the LPC filter, and include in your report a figure showing the amplitude spectrum of the speech segment (in dB) and the corresponding LPC filter response, as a function of frequency in Hz. The model order should be chosen such that the LPC filter provides a reasonable fit to the formant structure. Estimate the first three formant frequencies of the vowel, and the mean fundamental frequency.

Synthesis

Generate a periodic impulse train (each impulse should be of unit-amplitude and one sample in 1 width) with the same fundamental frequency as the original vowel segment, and of roughly a second in length. This will be the simulated periodic source for voiced sounds in the source-filter model of speech production. Filter the pulse train using the LPC filter determined above, and listen to the synthesized speech. Experiment with different AR model orders and segment lengths.

Make an informal subjective assessment of the final synthesized speech quality.

[Faiz Ahmad Khan]

Ikr.