| 摘要 |
The synthesizer comprises a lattice filter (TV) which simulates the vocal tract and generates speech samples by processing samples of excitation waveforms on the basis of suitable coefficients. The excitation waveforms, which are either periodical, in case of synethesis of a voiced sound or pseudorandom, in case of unvoiced sound, are supplied by respective generators (EP, EC) connectable to the filter (TV) upon command of a signal indicating the voiced-unvoiced nature of the sound. The filter coefficients and the information on the nature of the sound, together with the pitch period in case of voiced sounds and the sound intensity, are supplied to filter TV and to the excitation generators (EC, EP) by an external unit (UE), where they are stored, through a plurality of input modules (INa... INn) and a control unit (UC) acting as an interface towards the external unit (UE). The input modules (INa... INn) effect a temporary storage of the synthesis parameters supplied by the external unit, and updates the filter coefficients at the beginning of each pitch period, in case of voiced sound, or at the beginning of a validity interval in case of unvoiced sound.
<??>The input modules are associated each to a synthesizer channel, and the excitation generators (EC, EP) and the filter (TV) are time division multiplexed over the various channels of the synthesizer. |
