Abstract:

Applications of the micropower impulse radar (MIR) to speech research at the Lawrence Livermore National Laboratory has produced potentially new methods of speech processing. They include the accurate calculation of vocal tract transfer functions, formant, and pitch analysis, and basic phoneme synthesis. These speech parameters have traditionally been in the realm of all-pole LPC calculations. Related research using the MIR radar has supplied an increasingly accurate voiced excitation function, which makes possible transfer function calculations using both poles and zeros, yielding more accurate formant information and more natural sounding synthesis. This paper compares the newly obtained results with traditional LPC and cepstral approaches and demonstrates the improvements based on experimental data from several male and female subjects. The radar data also allow extremely accurate pitch tracking, which is simpler and more robust than that calculated by traditional means. This information can significantly enhance acoustic-based speech processing by allowing pitch adaptive processing.