Phase unwrapping methods for quadratic phase interpolation in voiced speech sythesis

This paper considers the use of a quadratic polynomial for phase interpolation in voiced speech synthesis using the multi-band excitation (MBE) model. The problem of phase unwrapping when using quadratic interpolation, originally proposed by Griffin and Lim (1988), is examined. In addition to that, another three new methods for phase unwrapping are studied. For the purpose of comparing the different unwrapping methods used for quadratic interpolation, the four unwrapping methods are used to synthesize voiced speech using the MBE model. Both the theoretical analysis and simulation results show that the fourth phase unwrapping method outperforms the other methods for voiced speech synthesis.