国产核心器件构建多通道模拟量采集系统的精度分析与设计

Accuracy Analysis and Design of Multi-Channel Analog Acquisition Systems Constructed by Domestic Key Components

摘要:

现代卫星驱动控制系统对模拟量的采集通道和采集精度的要求日益增高，而现有技术缺乏对系统采集精度的系统研究，导致核心器件国产化替代过程中经常出现采集精度无法满足预期的问题。针对该问题，对基于多通道模拟开关和开关电容模数转换器（ADC）构建的多通道模拟量采集系统的精度影响因素进行了系统研究，分别建立了系统静态误差和动态误差分析模型，为关键器件选型建立了理论依据，并通过基于国产16通道模拟开关和8通道12位开关电容ADC设计的128通道模拟量采集系统进行了验证。结果表明：该系统的绝对测量精度优于1.6mV，小于ADC自身引入的误差估算值1.883mV；说明基于静态误差和动态误差模型建立的核心器件选型依据对设计和改进多通道模拟量采集系统的测量精度具有普遍指导意义。

Abstract:

Channel numbers and measurement accuracy of analog acquisition systems are increasingly demanded in modern satellite drive and control systems. However, existing technology lacks systematic research on the acquisition accuracy of the system. As a result, acquisition accuracy often fails to meet expectation in the substitution process of domestic key components. To solve this problem, factors affecting the accuracy of the multi-channel analog acquisition system, which is based on multi-channel analog switch and switched capacitor analog-to-digital converter (ADC), are studied systematically. The analysis models of the static and dynamic error of the system are respectively build, and theoretical basis for key components selection is established, which are verified by a 128-channel analog acquisition system based on the domestic 16-channel analog switch and 8-channel 12-bit switched capacitor ADC. The results show that the absolute measurement accuracy of the system is better than 1.6 mV, which is better than the estimated error of 1.883 mV introduced by the ADC itself; and it indicates that the established criteria for key components selection based on the static and dynamic error models has general guiding significance for designing and improving the measurement accuracy of multi-channel analog acquisition systems.