In this paper, an HNM based scheme is developed to synthesize Mandarin syllable signals. With this scheme, a Mandarin syllable can be recorded just once, and diverse prosodic characteristics can be synthesized for it without suffering significant signal-quality degradation. In our scheme, a synthetic syllable’s duration is subdivided to its comprising phonemes and a piece-wise linear mapping function is constructed. With this mapping function, a control point on a synthetic syllable can be mapped to locate its corresponding analysis frames. Then, the analysis frames’ HNM parameters are interpolated to obtain the HNM parameters for the control point. Furthermore, for pitch-height adjusting, another timbre-preserving interpolation is performed on the HNM parameters of a control
point. Thereafter, signal samples are synthesized according to the HNM synthesis equations rewritten here. This HNM based scheme has been programmed to synthesize Mandarin speech. According to the perception tests, our HNM based scheme is found to be apparently better than a PSOLA based scheme in signal clarity, i.e. much clearer and no reverberation.