1. Analysis & Synthesis The Vocoder and its related technology

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

7. (Slightly less) Simplified Model of Speech Production Glottal model Noise source Filters voiced unvoiced Coupling Speech Impulse train x x Gain v Gain u pitch V/uv bit Filter spec

8. Glottal Waveform Caricature Glottis open (nonlinear) Glottis closed (decoupled)

9. Channel Vocoder, Synthesizer component

10. Channel Vocoder, Analyzer component

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

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

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

14. Fine structure and Spectral Envelope

15. Narrow and wideband filterbank spectral analyses

16. Wideband spectrogram

17. Figure 3.5: Narrow band spectrogram Narrowband spectrogram

18. Source-Filter Separation by Cepstral Analysis

19. LPC spectral envelope estimation

20. 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”

21. http://ptolemy.eecs.berkeley.edu/~eal/audio/vocoder. html Ed Lee Vocoder Page

22. http://www.sirlab.de/linux/descr_vocoder.html Linux Vocoder Page