An FPGA-based embedded wideband audio codec system

Wideband audio codec (WAC) improves the voice quality in the hand-free communication system. It allows the telephone conversation to sound more natural and subtle. In this paper, the G.729.1 WAC is ported to Altera Nios II platform and then optimized with dedicated hardware FIR filter and MDCT accelerators to improve the performance for faster operation. The hardware FIR filter and MDCT accelerators are each designed as a customized Altera on-chip Avalon bus device to work with the Nios II embedded processor. The cores are implemented in Verilog and incorporated with the Aletra SOPC builder. It was simulated with Altera ModelSim. The performance of the WAC with the software only and that with the hardware FIR filterbank and MDCT were compared. The embedded WAC system was implemented in the Stratix II DSP Development Kit with Altera Quartus II and Embedded development toolset. The system currently works at 100 MHz and utilizes 48% of the Altera Stratix II EP2S60 FPGA logic cell resources.