一种提高ADC分辨率的阶梯叠加法

Staircase function addition method of improving the resolution of analog-to-digital converter

常用的提高ADC分辨率的分段转换法存在"漏码",甚至无法保证A/D转换的单调性,而使效果相当有限。本文介绍一种能提高ADC分辨率的阶梯叠加法,该法令模拟输入电压Vi与由LSB换算得来的阶梯电压VS(p)的P种不同数值分别叠加,所得之和依次作为ADC的输入电压Vi,并对ADC的P个输出数码NOp求取平均值,作为整个数据系统的输出数码。理论上该法能实现LSB的细分,将原ADC的分辨率提高数位。通过3类实验,结果证明了理论的正确,同时对改进ADC电路设计具有重要借鉴意义。

The segmentation conversion commonly used to improve the resolution of analog-to-digital converter can cause a missing-code error, even can＇t ensure the monotonicity of analog-to-digital converter, so its effect of improving the resolution is limited. This paper introduces a staircase function addition method that can improve the resolution of analog-to-digital converter, the method let the input voltage of analog Vi add respectively with P kind of values of staircase function voltage VS（ p ） converting from LSB, its sum is taken as the input voltage V＇i of ADC in turn,and average the values of P kind of output NOp of ADC, and the average value would he taken as the output of the whole system. Theoretically, the staircase function addition method can fractionize LSB, so that adds several bits of the resolution basing primary. This theory has been proven to be right by three groups of test, it is very significant to improve the designing of the ADC circuitry.