A GSM Vocoder using a flexible DSP core

Abstract

We present a speech vocoder that will be used in GSM mobile systems to convert 300-3400 Hz speech to 13 Kbit/s digital bit stream. This 350 000 transistor chip was designed in a CMOS 1.0 ¿m technology in collaboration with VLSI Technology. The architecture was defined with a flexible 13 MHz DSP core developped at CNET. The GSM 06 series recommendations are met with a low 2.7 MIps. The DSP core has a VLIW microprogrammed Harvard architecture. The ROM program is obtained without writing assembler using a C-to-microcode compiler targeted to the architecture.