Design and implementation of AMBE based Voice Codec Module over custom FPGA platform

This paper presents the design and implementation of a Voice Codec Module (VCM) over a Field Programmable Gate Array (FPGA) platform for low bit rate voice communication using Vocoder AMBE (Advanced Multi Band Excitation)-2000 and Codec AD-73311. Low bit rate voice communication has become essential to many applications like digital radio, satellite communication, underwater acoustic communication etc. where bandwidth is at a premium and voice intelligibility is imperative. The hardware circuit of VCM is designed using FPGA instead of following the traditional DSPs/Microcontrollers approach so as to fulfill the objective of designing all the major subsystems of voice/data communication baseband unit inside a single FPGA chip. The Codec AD73311 used is a high performance A/D & D/A chip with programmable input and output gain control, and AMBE-2000 is the vocoder which is based on the AMBE compression algorithm. Using this VCM, the call voice is clear and legible at the rate of 2.0~2.4 Kbps which is very low compression bit rate.