| 摘要 |
An implementation of the present invention comprises a voice encoder and decoder method and system that uses voice excitation, eliminating the voice/unvoiced pitch tracking, and the first formant up to 2400 Hertz, does not use pulse code modulation encoding, but uses the zero crossings only of the first formant, dividing by two and sampling at 2400 Hertz. The resulting combination uses half of the bit rate for excitation and the remainder for short term spectrum analysis. The spectrum is updated each 20 milliseconds using 48 bits per frame. The decoder extracts the excitation, multiplies it by two and uses a Hanning modified sawtooth and spectral flattening to excite the spectrum generator. This waveform produces both even and odd harmonics for both periodic (voiced) and aperiodic (unvoiced) frequencies and gives naturalness to all languages and speakers.
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