Design And FPGA Implementation Of Audio Communication Over-sampling DAC

Audio communication is an important part of telecommunication.Communication advanced from analog era to digital communication and digital processing. Digital-to-analog Converter(DAC) based on∑-Δnoise shaping and over-sampling could convert digital signal to high resolution analog signal.There is extensive application value in audio converting.And this structure has many advantages,such as its ultimate low mismatch,high reliability and being able to embed to other chip system as an IP core,it's more important that high resolution and dynamic range could be get comparing to other kind of DAC structures.As for non-linearity and non-stability,it's difficult to realize the design and implement the high-order∑-Δmodulator.This paper uses many empirical principal and method for references,firstly the basic principle of∑-Δmodulator is described, then the design flow of modulator that has common structure is presented,in the end the design of stable,high-order and high-resolution modulator is implemented. According to the market requirement,the performance parameters of the design scheme is specified.Based on the scheme,a 16-bit resolution,full-scale input range and three-order 128 over-sampling modulator is designed in this paper.∑-Δstructure is applied in this paper,the quantizer bit,over-sampling ratio and order of the modulator is designed depending on the system requirement.On the analysis the stability of high-order single-loop modulator,the six bit quantization three-order single-loop structure modulator is implemented.With the 16bit input signal, a 90dB SNR is achieved.This design is implemented on the Cyclone FPGA platform, with the real-time audio signal verification realized.And the verification demonstrates that the output SNR could satisfy the resolution requirement of 16bit data-conversion application by the DAC module,which possesses compatibility and universal ability.This design could be re-used widely in other system as a IP core,which has application performance and innovation.