高分辨率地震仪ΣΔA/D转换器的噪声整形

Noise shaping in ΣΔA/D converter in high resolution seismograms

通过对 ΔA/D转换器中的 Δ调制器的分析 ,提出了对 ΔA/D转换器的噪声整形的基本理论 ,为设计具有高分辨率的地震数据采集站提供了理论依据 .结合ΔA/D转换器的具体电路结构 ,分析了基本环路滤波器和高阶滤波器滤波方式的噪声整形技术对A/D转换器分辨率的影响 .结果表明 ,在 ΔA/D转换器中 ,利用适当阶数的高阶 Δ调制器的噪声整形作用 ,可以使信号在A/D转换时的量化噪声转移到有效信号频段之外 ,再使用数字滤波器滤除带外噪声后 ,可以有效地实现地震仪中 2

Through the analysis of noise shaping in Δ modulator, the basic theory of noise shaping can be obtained and thus can provide theoretical support for the implementation of ΔA/D converter in high resolution seismograms. With specificΔ modulation circuit, this paper has analyzed the theory of noise shaping technique and its effects on the resolution of A/D converters with basic and high order loop filter. It has shown that through Δ modulator of proper order, the quantization noise generated in signal's A/D conversion process can be shifted out of the valid signal frequency band, and then can be filtered out by digital filter, thus a 24-digit high resolution A/D conversion can be realized effectively in seismograms.