应用调制解调技术实现低漂移地震数据采集的技术分析与研究
|
摘要
现代化的地震观测系统是基于数字化技术的观测网络,观测信号在地震台站的观测点进行数字化,经网络传输、汇集后由计算机系统进行处理和存贮。地震数据采集是数字化地震观测的重要环节,其核心功能是将地震观测传感器输出的模拟信号转换为数字信号,模拟数字转换器的技术水准在很大程度上决定了数据观测质量。地震信号为低频信号( 10~(-3) Hz～10~2Hz),而数据采集器在低频段会产生1/ f噪声的特性,影响信号观测精度。基于此本论文在理论算法上对此问题做了一些初步的探讨。
本论文首先介绍了地震信号的种类,数模转换的基本原理。然后分析了数据采集器短路噪声的1/ f特性,为削弱1/ f噪声的影响,分析目前现有的自稳零技术(autozeros)的一些特点,基于此技术提出了改进的差分算法。研究结果表明,两种方法在本质上都是对基带信号的调制,从而实现了削弱1/ f噪声对测量精度的影响。结合两种技术最终提出调制解调的计算模型,并用一组输入信号对模型进行检验,结果表明调制解调模型可以有效的去处1/ f噪声的影响。本论文又使用实际电路记录的数据进行分析,旨在通过调制解调系统来观察低频噪声是否有效的消除。结果达到了预期的目标。
本论文在方波基础之上提出伪随机序列作为调制解调信号的算法。伪随机序列具有保密与抗干扰的特点,从仿真的结果可以得出,伪随机序列用作调制解调信号也可以消除1/ f噪声的影响,具有与方波类似的输出结果。
本论文在调制解调的基础之上,还提出了改进输出信噪比的算法。由于调制解调系统是线性系统,所以频谱在搬移过程避开了1/ f噪声的频段,但没有改变噪声本底。基于此本文从能量损失的角度分析了方波与正弦信号作为调制解调序列的优劣提出了加权平均的算法。从理论上论证了加权平均算法的正确性,并且实验数据也表明信噪比有一定程度的提高。
Modern seismic survey system is based on the observation network of digital technology. Signals in the seismic stations are digitized, transmitted by networks, collected by computer systems for process and storage. Digital seismic data acquisition is an important part in earthquake observation, the key function is converting analog signals into digital signals, and analog-digital converter technology standards largely determine the quality of the data observation. Seismic signals mostly distribute in the low-frequencies ( 10~(-3) Hz- 10~3Hz), and data acquisition will produce 1/f noise characteristics to the observation accuracy in the low frequency range. The paper has done some preliminary discussions on this issue based on an algorithm theory.
First, the paper describes the types of seismic signals, the composition of seismic observation network and principles of digital-analog conversion. Then the paper analyzes the short circuit 1/f noise characteristics in data acquisitions, and some features of the auto-zero technique for weakening the 1/f noise. Based on this technology, the improved algorithm is proposed.
The results show that two methods essentially modulate base band signals to high frequency range and weaken the impact of 1/f noise on measurement accuracy. The paper finally combines two technologies and proposes the modulation algorithm. A set of input signals were tested to show that 1/f noise can effectively be weakened through the modulation model. The paper also uses the actual data to analyze the result whether data through the modulation model to observe low-frequency noise is effectively eliminated. The result is optimistic.
The paper also use pseudo-random sequence as the signal modulation and demodulation algorithm based on the proposed square-wave. Pseudo-random sequences have the characteristics of confidentiality and interference; pseudo-random sequence can also be used as a modulated signal to eliminate 1 / f noise, with a similar square wave output from the simulation. Confidentiality can be good for the occasion. The paper, based on the modem, also proposed an algorithm to improve the output signal to noise ratio. The modulated system is linear system, so the spectrum in the moving process to avoid the 1 / f noise band, but did not change the noise floor. The paper also analyze the energy loss of square wave and sine wave modulation and demodulation sequence as a weighted average for proposing the algorithm and prove the correctness of the weighted average algorithm in theory. Experimental data also show that the signal to noise ratio has improved to some extent, and are in good Consistent with the calculated value.
本论文首先介绍了地震信号的种类,数模转换的基本原理。然后分析了数据采集器短路噪声的1/ f特性,为削弱1/ f噪声的影响,分析目前现有的自稳零技术(autozeros)的一些特点,基于此技术提出了改进的差分算法。研究结果表明,两种方法在本质上都是对基带信号的调制,从而实现了削弱1/ f噪声对测量精度的影响。结合两种技术最终提出调制解调的计算模型,并用一组输入信号对模型进行检验,结果表明调制解调模型可以有效的去处1/ f噪声的影响。本论文又使用实际电路记录的数据进行分析,旨在通过调制解调系统来观察低频噪声是否有效的消除。结果达到了预期的目标。
本论文在方波基础之上提出伪随机序列作为调制解调信号的算法。伪随机序列具有保密与抗干扰的特点,从仿真的结果可以得出,伪随机序列用作调制解调信号也可以消除1/ f噪声的影响,具有与方波类似的输出结果。
本论文在调制解调的基础之上,还提出了改进输出信噪比的算法。由于调制解调系统是线性系统,所以频谱在搬移过程避开了1/ f噪声的频段,但没有改变噪声本底。基于此本文从能量损失的角度分析了方波与正弦信号作为调制解调序列的优劣提出了加权平均的算法。从理论上论证了加权平均算法的正确性,并且实验数据也表明信噪比有一定程度的提高。
Modern seismic survey system is based on the observation network of digital technology. Signals in the seismic stations are digitized, transmitted by networks, collected by computer systems for process and storage. Digital seismic data acquisition is an important part in earthquake observation, the key function is converting analog signals into digital signals, and analog-digital converter technology standards largely determine the quality of the data observation. Seismic signals mostly distribute in the low-frequencies ( 10~(-3) Hz- 10~3Hz), and data acquisition will produce 1/f noise characteristics to the observation accuracy in the low frequency range. The paper has done some preliminary discussions on this issue based on an algorithm theory.
First, the paper describes the types of seismic signals, the composition of seismic observation network and principles of digital-analog conversion. Then the paper analyzes the short circuit 1/f noise characteristics in data acquisitions, and some features of the auto-zero technique for weakening the 1/f noise. Based on this technology, the improved algorithm is proposed.
The results show that two methods essentially modulate base band signals to high frequency range and weaken the impact of 1/f noise on measurement accuracy. The paper finally combines two technologies and proposes the modulation algorithm. A set of input signals were tested to show that 1/f noise can effectively be weakened through the modulation model. The paper also uses the actual data to analyze the result whether data through the modulation model to observe low-frequency noise is effectively eliminated. The result is optimistic.
The paper also use pseudo-random sequence as the signal modulation and demodulation algorithm based on the proposed square-wave. Pseudo-random sequences have the characteristics of confidentiality and interference; pseudo-random sequence can also be used as a modulated signal to eliminate 1 / f noise, with a similar square wave output from the simulation. Confidentiality can be good for the occasion. The paper, based on the modem, also proposed an algorithm to improve the output signal to noise ratio. The modulated system is linear system, so the spectrum in the moving process to avoid the 1 / f noise band, but did not change the noise floor. The paper also analyze the energy loss of square wave and sine wave modulation and demodulation sequence as a weighted average for proposing the algorithm and prove the correctness of the weighted average algorithm in theory. Experimental data also show that the signal to noise ratio has improved to some extent, and are in good Consistent with the calculated value.
引文
1.李文莉,任文银,“数字信号处理”基本分析工具相互联系及转换关系分析.新乡学院学报:自然科学版, 2010. 27(5): p. 85-87.
2.林爱英, et al., DFT在信号谱分析中的应用.安徽工业大学学报:自然科学版, 2011. 28(2): p. 192-196.
3.夏哲雷,自动稳零电桥放大器.自动化与仪表, 1993. 8(4): p. 49-50.
4.高素玲,吴欣慧, FIR数字滤波器的实现方法比较.黑龙江大学工程学报, 2010: p. 96-99.
5.许天宏,王永德, Gold序列相关特性分析的某些新结果.四川大学学报:自然科学版, 1994. 31(3): p. 347-351.
6.董渊文,官洪运,胡辉, GPS接收机伪码跟踪技术研究及仿真.系统仿真学报, 2006. 18(11): p. 3209-3211.
7.温艳,邵毅, IIR数字滤波器的设计及仿真.微计算机信息, 2010: p. 229-230.
8.李娟, MATLAB平台下的FIR数字滤波器设计与分析.高师理科学刊, 2010: p. -.
9.郝娟,徐沛文, MATLAB在FIR数字带通滤波器设计中的应用.电脑与电信, 2011: p. 49-51.
10.郝娟,徐沛文, MATLAB在FIR数字带通滤波器设计中的应用.电脑与电信, 2011: p. 49-51.
11.唐俊波,费秀海,尹国成, MATLAB在数学教学中的几类应用.保山学院学报, 2010. 29(5): p. 84-88.
12.张春生,钱萌, MATLAB在数字滤波器设计中的应用探索.中国电力教育:下, 2011: p. 156-157.
13.王福杰,潘宏侠, MATLAB中几种功率谱估计函数的比较分析与选择.电子产品可靠性与环境试验, 2009. 27(6): p. 28-31.
14.辛肖明,陈琼, m序列优选对及平衡Gold码序列.北京理工大学学报, 1990. 10(4): p. 106-113.
15.钱荣毅,曾校丰, REFTEK宽频地震观测仪器系统和野外数据采集.物探装备, 2004. 14(1): p. 52-54.
16.王荔芳,周晓华,陶燕林, Simulink在RLC串联的动态电路分析中的应用.现代电子技术, 2010. 33(24): p. 37-39.
17.杨蔚原, Welch功率谱估计方法的参数选择.环境技术, 2009. 27(5): p. 23-27.
18.张峰,石现峰,张学智, Welch功率谱估计算法仿真及分析.西安工业大学学报, 2009. 29(4): p. 353-356.
19.张登奇,李宏民,李丹,按时间抽取的基2FFT算法分析及MATLAB实现.电子技术(上海), 2011. 38(2): p. 75-77.
20.解翔,卫红凯,马珂,窗函数对传统功率谱估计精度的影响.舰船电子对抗, 2009. 32(2): p. 84-86.
21.罗福龙,地震数据采集系统综述和展望.中国石油勘探, 2007. 12(2): p. 41-46.
22.张佳明, et al.,非参数模型谱估计算法性能比较.天津理工大学学报, 2009. 25(4): p. 19-22.
23.华玲,常建平,高阶FIR滤波器的计算机设计与FPGA实现.现代电子技术, 2011. 34(2): p. 99-102.
24.邓玉清,唐宁,曹杰,高精度音频∑-ΔDAC的设计.电视技术, 2011. 35(7): p. 56-58.
25.张玉超,徐科军,叶旭,互相关运算中的两个关键问题研究.电气电子教学学报, 2011. 33(1): p. 27-28.
26.邢务强,钮金鑫,基于AR模型的功率谱估计.现代电子技术, 2011. 34(7): p. 49-51.
27.么艳平,史红,王广德,基于Matlab/Simulink的调制解调分析.科协论坛:下半月, 2011: p. 40-41.
28.李露,史振威,周付根,基于Matlab/Simulink的幅度调制与解调综合实验设计.实验室研究与探索, 2011. 30(1): p. 96-99.
29.梁广颖,基于MATLAB的64阶FIR滤波器的设计.科技信息, 2011: p. I0074-I0074.
30.杨燕,基于Matlab的DSP信号采集系统的总体设计.制造业自动化, 2010: p. 116-118.
31.聂仙娥, et al.,基于Matlab的FIR型希尔伯特变换器设计.现代电子技术, 2011. 34(7): p. 113-116.
32.刘海波,基于MATLAB的IIR数字滤波器的研究.科技创新导报, 2010: p. 35-35.
33.谢黎明,郑锐,基于Matlab的IIR数字滤波器设计.机械与电子, 2011: p. 28-30.
34.龙安,陈华,基于MATLAB的频率采样法设计FIR滤波器.广西科学院学报, 2011. 27(1): p. 68-70.
35.黄宗卫,基于Matlab的数字滤波器的设计.舰船电子对抗, 2011. 34(1): p. 116-117.
36.黄琴, et al.,基于MATLAB的信号与系统虚拟实验系统设计.计算机与现代化, 2010: p. 186-188.
37.贾怀义,毕红军,等,基于m序列扩频码的研究.北方交通大学学报, 2001. 25(3): p. 85-88.
38.伊鑫,曲爱华,基于Welch算法的经典功率谱估计的Matlab分析.现代电子技术, 2010: p. 7-9.
39.冯炎,尼玛扎西,基于频带间相关性的加权噪声功率谱估计.信息与电子工程, 2010. 8(4): p. 431-435.
40.沈志远,王黎明,陈方林,基于有限长序列分析的Welch法谱估计研究.计算机仿真, 2010: p. 391-395.
41.王辉, et al.,基于斩波自动稳零运算放大器的激光器平均光功率控制.今日电子, 2004: p. 45-47.
42.苏国军,李文江,汪晋,基于直接序列扩频的电力线通信及其应用.辽宁工程技术大学学报:自然科学版, 2005: p. 129-131.
43.黄剑明,施志勇,保铮,截短平衡Gold码的统计特性分析.系统工程与电子技术, 2006. 28(5): p. 646-649.
44.王林,芮国胜,田文飚,宽带短波信道模拟器中数字下变频的实现.无线电通信技术, 2010. 36(6): p. 44-47.
45.李威,陈祖斌,邱飞,宽频地震仪数据采集系统的研制.微计算机信息, 2008. 24(22): p. 80-81.
46.王家成,朱勇,数字信号处理综合实验设计探讨.阜阳师范学院学报:自然科学版, 2011. 28(1): p. 99-102.
47.干昌浩,随机振动功率谱估计方法研究.中国高新技术企业, 2010: p. 21-23.
48.熊睿佳,胡万利,伪随机m序列特性及C语言实现.工程地球物理学报, 2011. 8(1): p. 110-112.
49.蔡睿,伪随机序列的产生及性能简介.安徽建筑, 2001. 8(2): p. 96-98.
50.支冬栋,卫红凯,杜斌,现代谱估计法中几种不同模型参数估计法的比较.舰船电子对抗, 2009. 32(1): p. 100-102.
51.刘传辉,现代谱估计方法分析.科学时代, 2010: p. 192-193.
52.张猛,王晓峰,信号与系统建模与仿真.长春大学学报, 2010. 20(8): p. 63-65.
53.李巍,邓建国,正交频分复用码分多址信号峰均功率比特性的研究.西安交通大学学报, 2004. 38(10): p. 1085-1089.
54.赵林军,刘乃安,中频数字化扩频测距系统的实现.无线电工程, 2009. 39(1): p. 49-50.
55.肖麟芬,自动调零放大器在应变测试仪中的应用.计量技术, 2007: p. 72-74.
56. Reinoud Sleeman, Arie van Wettum, and Jeannot Trampert, Three-Channel Correlation Analysis: A New Technique to Measure Instrumental Noise of Digitizers and Seismic Sensors. Bulletin of the Seismological Society of America, 2006. pp. 258–271
57. Crystal Semiconductor Corporation High Performance Data Acquisition and Hi-Fidelity Audio Applications Seminar
58. High-Performance, Two-Channel, 24-Bit, 216kHz Sampling Multi-Bit Delta-Sigma Analog-to-Digital Converter. PCM4222. 2007. Texas Instrument
59. John Wright, Don't Be Fooled By Voltage Reference Long-Term Drift and Hysteresis. Design Note 229
2.林爱英, et al., DFT在信号谱分析中的应用.安徽工业大学学报:自然科学版, 2011. 28(2): p. 192-196.
3.夏哲雷,自动稳零电桥放大器.自动化与仪表, 1993. 8(4): p. 49-50.
4.高素玲,吴欣慧, FIR数字滤波器的实现方法比较.黑龙江大学工程学报, 2010: p. 96-99.
5.许天宏,王永德, Gold序列相关特性分析的某些新结果.四川大学学报:自然科学版, 1994. 31(3): p. 347-351.
6.董渊文,官洪运,胡辉, GPS接收机伪码跟踪技术研究及仿真.系统仿真学报, 2006. 18(11): p. 3209-3211.
7.温艳,邵毅, IIR数字滤波器的设计及仿真.微计算机信息, 2010: p. 229-230.
8.李娟, MATLAB平台下的FIR数字滤波器设计与分析.高师理科学刊, 2010: p. -.
9.郝娟,徐沛文, MATLAB在FIR数字带通滤波器设计中的应用.电脑与电信, 2011: p. 49-51.
10.郝娟,徐沛文, MATLAB在FIR数字带通滤波器设计中的应用.电脑与电信, 2011: p. 49-51.
11.唐俊波,费秀海,尹国成, MATLAB在数学教学中的几类应用.保山学院学报, 2010. 29(5): p. 84-88.
12.张春生,钱萌, MATLAB在数字滤波器设计中的应用探索.中国电力教育:下, 2011: p. 156-157.
13.王福杰,潘宏侠, MATLAB中几种功率谱估计函数的比较分析与选择.电子产品可靠性与环境试验, 2009. 27(6): p. 28-31.
14.辛肖明,陈琼, m序列优选对及平衡Gold码序列.北京理工大学学报, 1990. 10(4): p. 106-113.
15.钱荣毅,曾校丰, REFTEK宽频地震观测仪器系统和野外数据采集.物探装备, 2004. 14(1): p. 52-54.
16.王荔芳,周晓华,陶燕林, Simulink在RLC串联的动态电路分析中的应用.现代电子技术, 2010. 33(24): p. 37-39.
17.杨蔚原, Welch功率谱估计方法的参数选择.环境技术, 2009. 27(5): p. 23-27.
18.张峰,石现峰,张学智, Welch功率谱估计算法仿真及分析.西安工业大学学报, 2009. 29(4): p. 353-356.
19.张登奇,李宏民,李丹,按时间抽取的基2FFT算法分析及MATLAB实现.电子技术(上海), 2011. 38(2): p. 75-77.
20.解翔,卫红凯,马珂,窗函数对传统功率谱估计精度的影响.舰船电子对抗, 2009. 32(2): p. 84-86.
21.罗福龙,地震数据采集系统综述和展望.中国石油勘探, 2007. 12(2): p. 41-46.
22.张佳明, et al.,非参数模型谱估计算法性能比较.天津理工大学学报, 2009. 25(4): p. 19-22.
23.华玲,常建平,高阶FIR滤波器的计算机设计与FPGA实现.现代电子技术, 2011. 34(2): p. 99-102.
24.邓玉清,唐宁,曹杰,高精度音频∑-ΔDAC的设计.电视技术, 2011. 35(7): p. 56-58.
25.张玉超,徐科军,叶旭,互相关运算中的两个关键问题研究.电气电子教学学报, 2011. 33(1): p. 27-28.
26.邢务强,钮金鑫,基于AR模型的功率谱估计.现代电子技术, 2011. 34(7): p. 49-51.
27.么艳平,史红,王广德,基于Matlab/Simulink的调制解调分析.科协论坛:下半月, 2011: p. 40-41.
28.李露,史振威,周付根,基于Matlab/Simulink的幅度调制与解调综合实验设计.实验室研究与探索, 2011. 30(1): p. 96-99.
29.梁广颖,基于MATLAB的64阶FIR滤波器的设计.科技信息, 2011: p. I0074-I0074.
30.杨燕,基于Matlab的DSP信号采集系统的总体设计.制造业自动化, 2010: p. 116-118.
31.聂仙娥, et al.,基于Matlab的FIR型希尔伯特变换器设计.现代电子技术, 2011. 34(7): p. 113-116.
32.刘海波,基于MATLAB的IIR数字滤波器的研究.科技创新导报, 2010: p. 35-35.
33.谢黎明,郑锐,基于Matlab的IIR数字滤波器设计.机械与电子, 2011: p. 28-30.
34.龙安,陈华,基于MATLAB的频率采样法设计FIR滤波器.广西科学院学报, 2011. 27(1): p. 68-70.
35.黄宗卫,基于Matlab的数字滤波器的设计.舰船电子对抗, 2011. 34(1): p. 116-117.
36.黄琴, et al.,基于MATLAB的信号与系统虚拟实验系统设计.计算机与现代化, 2010: p. 186-188.
37.贾怀义,毕红军,等,基于m序列扩频码的研究.北方交通大学学报, 2001. 25(3): p. 85-88.
38.伊鑫,曲爱华,基于Welch算法的经典功率谱估计的Matlab分析.现代电子技术, 2010: p. 7-9.
39.冯炎,尼玛扎西,基于频带间相关性的加权噪声功率谱估计.信息与电子工程, 2010. 8(4): p. 431-435.
40.沈志远,王黎明,陈方林,基于有限长序列分析的Welch法谱估计研究.计算机仿真, 2010: p. 391-395.
41.王辉, et al.,基于斩波自动稳零运算放大器的激光器平均光功率控制.今日电子, 2004: p. 45-47.
42.苏国军,李文江,汪晋,基于直接序列扩频的电力线通信及其应用.辽宁工程技术大学学报:自然科学版, 2005: p. 129-131.
43.黄剑明,施志勇,保铮,截短平衡Gold码的统计特性分析.系统工程与电子技术, 2006. 28(5): p. 646-649.
44.王林,芮国胜,田文飚,宽带短波信道模拟器中数字下变频的实现.无线电通信技术, 2010. 36(6): p. 44-47.
45.李威,陈祖斌,邱飞,宽频地震仪数据采集系统的研制.微计算机信息, 2008. 24(22): p. 80-81.
46.王家成,朱勇,数字信号处理综合实验设计探讨.阜阳师范学院学报:自然科学版, 2011. 28(1): p. 99-102.
47.干昌浩,随机振动功率谱估计方法研究.中国高新技术企业, 2010: p. 21-23.
48.熊睿佳,胡万利,伪随机m序列特性及C语言实现.工程地球物理学报, 2011. 8(1): p. 110-112.
49.蔡睿,伪随机序列的产生及性能简介.安徽建筑, 2001. 8(2): p. 96-98.
50.支冬栋,卫红凯,杜斌,现代谱估计法中几种不同模型参数估计法的比较.舰船电子对抗, 2009. 32(1): p. 100-102.
51.刘传辉,现代谱估计方法分析.科学时代, 2010: p. 192-193.
52.张猛,王晓峰,信号与系统建模与仿真.长春大学学报, 2010. 20(8): p. 63-65.
53.李巍,邓建国,正交频分复用码分多址信号峰均功率比特性的研究.西安交通大学学报, 2004. 38(10): p. 1085-1089.
54.赵林军,刘乃安,中频数字化扩频测距系统的实现.无线电工程, 2009. 39(1): p. 49-50.
55.肖麟芬,自动调零放大器在应变测试仪中的应用.计量技术, 2007: p. 72-74.
56. Reinoud Sleeman, Arie van Wettum, and Jeannot Trampert, Three-Channel Correlation Analysis: A New Technique to Measure Instrumental Noise of Digitizers and Seismic Sensors. Bulletin of the Seismological Society of America, 2006. pp. 258–271
57. Crystal Semiconductor Corporation High Performance Data Acquisition and Hi-Fidelity Audio Applications Seminar
58. High-Performance, Two-Channel, 24-Bit, 216kHz Sampling Multi-Bit Delta-Sigma Analog-to-Digital Converter. PCM4222. 2007. Texas Instrument
59. John Wright, Don't Be Fooled By Voltage Reference Long-Term Drift and Hysteresis. Design Note 229