基于FPGA的大动态范围数据采集系统设计

Design of Large Dynamic Range Data Acquisition System Based on FPGA

针对传统数据采集系统受动态范围限制,进行测量时对大信号易过载、小信号易丢失等问题,设计了一种基于FPGA的大动态范围多通道数据采集系统,讨论了噪声相关性与放大器增益对动态范围的影响。该系统采用一种分立式架构的双ADC同步采集单元,结合FPGA高速并行处理的特点进行数据融合,对前端可变增益放大电路实时控制,实现多通道数据采集系统对微小信号采集时的高分辨率以及对大信号采集时的高容差。对采用动态范围最大为108 dB的AD7768芯片研制的实验样机进行测试,结果表明其在64 kHz的采样频率下可达到160 dB以上的动态范围,系统采样精度达到0.1%,线性度优于0.005%,通道间相位精度达到±0.05°。

A large dynamic range multi-channel data acquisition system based on FPGA was designed to address the limitations of traditional data acquisition systems,such as signal overload for large signals and signal loss for small signals during measurements.The impact of noise correlation and amplifier gain on the dynamic range was discussed.The system employed a discrete architecture with synchronized dual ADC acquisition units and combined the high-speed parallel processing capabilities of FPGA for data fusion,real-time control of the front-end variable-gain amplification circuit was implemented,enabling high-resolution acquisition of small signals and high tolerance for large signals in the multi-channel data acquisition system.An experimental prototype using the AD7768 chip with a maximum dynamic range of 108 dB was tested,demonstrating a dynamic range exceeding 160 dBat a sampling frequency of 64 kHz.The system achieved a sampling accuracy of 0.1%,linearity better than 0.005%,and inter-channel phase accuracy of±0.05°.