A new fundamental frequency modification algorithm with transformation of spectrum envelope according to F/sub 0/

This paper proposes a new speech modification algorithm which makes it possible to change the fundamental frequency (F/sub 0/) while preserving high quality. One novel point of the algorithm is that the spectrum envelope is transformed according to amount of F/sub 0/ modification. Based on a codebook mapping formulation, transformation rules are generated using speech data uttered in a different F/sub 0/ range. The rules have two purposes: one is transforming the spectrum envelope of the low frequency band and the other is adjusting the balance between low band power and high band power. The proposed algorithm is applied to a text-to-speech system based on waveform concatenation, and good performance is confirmed by listening tests.