过采样技术在428XL系统中的应用
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摘要
本文首先对常规A/D转换和过采样技术进行了对比分析,阐述了过采样技术在抑制噪声、抗假频、噪声修整、扩大动态范围等方面的技术优势;然后详细介绍了过采样技术在428XL系统中的实现:428XL采用四阶增量调制器,过采样频率256kHz,以此为基础,构成了428XL地震信号采集通道,即输入滤波→256kHz的模数转换→数字滤波,其中,数字滤波分两级进行,第一级设在采集站内部,产生24位的4kHz的数字信号,第二级滤波设在电源站和交叉站内部,完成4kHz数字信号的存储、去除采样时滞,同时完成去假频滤波、根据实际的采样率抽取数据完成数据采集。最后分析了过采样等技术在FDU-428、LAU-428中的典型应用。
The paper firstly compared the conventional A/D technology with the over-sampling technology,expounded the technical advantages of over sampling technology in aspects of eliminating noise,anti-aliasing,noise shaping and expanding dynamic range;then introduced the implementation of over-sampling technique in 428XL system: the 428XL adopts 4-step increment modulator and 256kHz over-sampling rate,based on which the seismic signal acquisition channel is structured in the 428XL:input filter→256kHz A/D converter→digital filter,among which the digital filter is composed of two parts: the first one is inside FUD and generate 24-bit 4kHz digital signal,the second one is inside LAUL and LAUX,finishing the storage of 4kHz digital signal,eliminating sampling skew processing and finishing anti-aliasing filtering at the same time,and completing data acquisition by sorting data according actual sampling rate,finally analyzed typical application of over-sampling technique in FDU-428 andLAU-428.
The paper firstly compared the conventional A/D technology with the over-sampling technology,expounded the technical advantages of over sampling technology in aspects of eliminating noise,anti-aliasing,noise shaping and expanding dynamic range;then introduced the implementation of over-sampling technique in 428XL system: the 428XL adopts 4-step increment modulator and 256kHz over-sampling rate,based on which the seismic signal acquisition channel is structured in the 428XL:input filter→256kHz A/D converter→digital filter,among which the digital filter is composed of two parts: the first one is inside FUD and generate 24-bit 4kHz digital signal,the second one is inside LAUL and LAUX,finishing the storage of 4kHz digital signal,eliminating sampling skew processing and finishing anti-aliasing filtering at the same time,and completing data acquisition by sorting data according actual sampling rate,finally analyzed typical application of over-sampling technique in FDU-428 andLAU-428.
引文
1 Sercel.428XL Training course V3.0.2006
2刘益成,罗维炳编著.信号处理与过抽样转换器.电子工业出版社,1997
2刘益成,罗维炳编著.信号处理与过抽样转换器.电子工业出版社,1997
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