1. (Extremely) Simplified Model of Speech Production
Periodic
source
voiced
Filters
Coupling
Speech
unvoiced
Noise
source

2. Channel Vocoder, Synthesizer component

3. Channel Vocoder, Analyzer component

4. Vocoders: vocal tract synthesis
Short time spectral synthesis
Linear predictive synthesis
Cepstral synthesis
Formant synthesis

5. Vocoders: vocal tract analysis
Short time spectral analysis
Linear predictive analysis
Cepstral analysis
Formant analysis

6. Vocoders: vocal source analysis
Pitch detection
Voiced/unvoiced decision

7. Fine structure and Spectral Envelope

8. Narrow and wideband filterbank spectral analyses

9. Wideband spectrogram

10. Figure 3.5: Narrow band spectrogram

11. Source-Filter Separation by Cepstral Analysis

12. LPC spectral envelope estimation

13. Formant Analysis Peak picking from smoothed spectrum
Root-finding from LPC polynomial - finding second-order sections
In general, position more important than bandwidth
Deterministic or statistical analysis to find best formant “track”

14. Ed Lee Vocoder Page

15. Linux Vocoder Page

16. How does the speech sound with the middle spectrum differ from the left one? From the right?