非减性Dither与过采样技术在低频模拟采集系统中的应用

Application of Non-decreasing Dither and Oversampling Technology in Low Frequency Analog Acquisition System

Dither技术是提高多通道模拟采集系统动态性能的有效方法。通过分析Dither技术改善采集系统无杂散动态范围(SFDR)的原理,搭建了多通道模拟采集系统测试平台,通过FPGA控制A/DC对输入的满量程正弦信号采样,利用过采样和均值滤波技术来提高采集精度。实验结果表明:采集系统的动态性能明显改善,SFDR从71 dB提高到78 dB,SNR下降了1.2 dB。

The Dither method is an effective way to improve the dynamic performance of multi-channel analog acquisition system.By analyzing the principle that Dither technology improves the non spur-free dynamic rage(SFDR)of the acquisition system,a test platform for multi-channel analog acquisition system is built.FPGA controls ADC to collect sinusoidal signals of full scale input,and improves the acquisition accuracy by oversampling and mean filtering.The experimental results show that the dynamic performance of the acquisition system is obviously improved,SFDR increases from 71 dB to 78 dB,and SNR decreases by 1.2 dB.