Norichika Kumamoto

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.

New description language for DSP firmware conversion

DSPs (Digital Signal Processors) are widely used, especially in digital cellular phones. However, it is very difficult and time consuming to create firmware for DSPs. We have considered an improved firmware development system. This paper introduce a new DSP firmware description language. We demonstrate firmware conversion between two different DSPs using our new language.