基于积分过采样结构的高精确度模数转换器

High-accuracy Analog to Digital Convertor based on an integral over-sampling structure

设计了一种积分过采样结构的高精确度模数转换器,该种结构转换器具有较高的线性度,千赫兹级信号带宽,它和通用集成模数转换器相比具有更高的精确度性能和更高的采样率。该模数转换器主要由采样保持模块、电压电流变换模块、积分模块、集成模数模块、FPGA模块、参考源以及电源模块构成,利用积分变换处理和过采样技术来提高转换器的精确度和采样率。为验证积分过采样理论的正确性与可行性,本文设计18位积分过采样模数转换器,其具有双极性输入电压-2^+2 V,采样率10 k Hz。通过对该模数转换器进行理论计算和仿真得到有效位数17 bit,信噪比为104.06 d B,微分线性误差(DLE)均小于0.5 LSB,积分线性误差(ILE)均小于0.3 LSB。

This paper designs a high-accuracy Analog to Digital Converter(ADC)based on an integral over-sampling structure.This structure of the converter bears high linearity,kilohertz magnitude of signal bandwidth.It shows higher accuracy performance and higher sampling rate compared with the general integration ADC.This ADC is mainly composed of sampling and holding module,voltage and current conversion module,integral module,integration Analog to Digital(AD)module,Field Programmable Gate Array(FPGA)module,reference source and power module.Integral transform processing and over-sampling techniques are utilized to improve the accuracy and sampling rate of the converter.In order to verify the correctness and feasibility of the integral over-sampling theory,an 18 bit integral over-sampling ADC is designed and implemented,which has a bipolar input voltage from-2 V to+2 V and a sampling rate of 10 kHz.By theoretical calculation and simulations of the ADC,the results show that the effective number is 17 bit,the Signal-to-Noise Ratio is 104.06 dB,the Differential Linearity Error(DLE)is below 0.5 LSB and the Integral Linearity Error(ILE)is below 0.3 LSB.