Efficient PSI-CELP DSP implementation

Pitch Synchronous Innovation-Code Excited Linear Prediction (PSI-CELP) algorithm has been adopted as a standard speech codec in the new Japanese Personal Digital Cellular (PDC) system. In this paper, we present an efficient implementation scheme for the PSI-CELP algorithm with a Digital Signal Processor (DSP). A PSI-CELP algorithm features the PSI technique, which can improve speech quality to repeat a part of a stochastic codeword with pitch period. We propose a specialized function that can support DSP instructions to allow efficient PSI implementation. According to our practical estimation with the PSI-CELP standard specification, our method can greatly reduce the costs for both parts complexity and required memory space.