Bandwidth extension of narrowband speech using cepstral analysis

Abstract

This paper describes a vector quantization based algorithm that extends the bandwidth of narrowband speech into wideband speech. Cepstral analysis is used to represent the spectral envelope information and the wideband excitation is generated using fullwave rectification with spectral whitening. Objective and subjective tests conducted show great improvement in speech quality over the original narrowband speech. The algorithm can be implemented as a postprocessor without the need for any side information.