软件无线电中上下变频技术的设计和实现
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摘要
软件无线电(Software Radio)这一概念是在1992年5月,由美国MILTRE公司的Joe Mitola在美国国家远程会议上提出的。它的中心思想是:构造一个具有开放性、标准化、模块化的通用硬件平台,将各种功能,如工作频段、调制解调类型、数据格式、加密模式、通信协议等用软件来完成,并使宽带A/D和D/A转换器尽可能靠近天线,以研制出具有高度灵活性、开放性的新一代无线通信系统。而软件无线电这—新概念—经提出,就得到了全世界无线电领域的广泛关注。由于软件无线电所具有的灵活性、开放性等特点,使其不仅在军、民无线通信中获得了应用,而且在其他领域例如电子战、雷达、信息化家电等领域也得到了推广。因此对软件无线电进行深入的研究是具有重要的现实意思的。
本文主要研究的是基于现场可编程逻辑阵列(FPGA)的数字上下变频技术的设计和实现。文中首先介绍了软件无线电的基本概念和数字上下变频的相关基本理论及常用算法,接着介绍了FPGA的发展概况和应用前景,最后详细论述了如何设计和实现整个数字上下变频系统的几个主要功能模块。这几个模块主要分为数控振荡器模块,抽取滤波模块,脉冲成型滤波模块和插值滤波模块四个部分。在这个几个模块当中,作者第一个介绍的是结合了查找表(LUT)和坐标旋转矢量(CORDIC)算法的数控振荡器(NCO)模块。接下来介绍了积分梳状(CIC)滤波器和半带滤波器(HBF)相结合的多速率抽取滤波模块,并且为了补偿CIC滤波器的通带衰减,引入了二阶多项式(ISOP)补偿滤波器。最后介绍了采用多相插值结构的脉冲成形滤波模块器和采用了整形CIC(SCIC)滤波器的插值滤波模块。
The conception of Software Radio is raised by Joe Mitola of MILTRE on a conference. It’s clou is to construct a exoteric, normative, and blocking hardware platform, and use softwares to achieve different functions such as working frequency, the types of modulation and demodulation, data formating, encrypting mode, and communication protocols and so on, and make the board band A/D and D/A converter close to antenna, so as to develop a new kind of flexible and exoteric wireless communication system. Software Radio gains abroad attention as soon as this conception is put forward. Software Radio is not only used in military and civil wireless communication but also used in other fields, such as electronic war, radar, etc. Therefore, it is significant to make deep research and development on Software Radio.
This paper deals with the design and implementation of Digital Up Conversion and Digital Down Conversion based on the field-programmable gate array (FPGA). Firstly, the related theory of Digital Up Conversion, Digital Down Conversion and the foreground of FPGA are introduced. Then the development and implementation foreground are presented. Finally, the design and implementation of several important function modules are discussed in details. These modules are the numerically controlled oscillator(NCO), the decimating digital filter ,the pulse-shaping filter and the multiplierless interpolating digital filter. In these modules, the NCO module is introduced first combined with the algorithm look-up table (LUT) and Coordinate Rotation Digital Computer (CORDIC). Follow that the decimating digital filter including the cascade of cascade dintegrator-comb (CIC) filters and Half-Band filters (HBF) is introduced. Besides, second-order polynomials (ISOP) filter is used in order to compensate the CIC’spassband attenuation. In the end, the pulse-shaping filter with polyphase decomposition structure and the multiplierless interpolating digital filter consists of a sharpened CIC filter are discussed.
本文主要研究的是基于现场可编程逻辑阵列(FPGA)的数字上下变频技术的设计和实现。文中首先介绍了软件无线电的基本概念和数字上下变频的相关基本理论及常用算法,接着介绍了FPGA的发展概况和应用前景,最后详细论述了如何设计和实现整个数字上下变频系统的几个主要功能模块。这几个模块主要分为数控振荡器模块,抽取滤波模块,脉冲成型滤波模块和插值滤波模块四个部分。在这个几个模块当中,作者第一个介绍的是结合了查找表(LUT)和坐标旋转矢量(CORDIC)算法的数控振荡器(NCO)模块。接下来介绍了积分梳状(CIC)滤波器和半带滤波器(HBF)相结合的多速率抽取滤波模块,并且为了补偿CIC滤波器的通带衰减,引入了二阶多项式(ISOP)补偿滤波器。最后介绍了采用多相插值结构的脉冲成形滤波模块器和采用了整形CIC(SCIC)滤波器的插值滤波模块。
The conception of Software Radio is raised by Joe Mitola of MILTRE on a conference. It’s clou is to construct a exoteric, normative, and blocking hardware platform, and use softwares to achieve different functions such as working frequency, the types of modulation and demodulation, data formating, encrypting mode, and communication protocols and so on, and make the board band A/D and D/A converter close to antenna, so as to develop a new kind of flexible and exoteric wireless communication system. Software Radio gains abroad attention as soon as this conception is put forward. Software Radio is not only used in military and civil wireless communication but also used in other fields, such as electronic war, radar, etc. Therefore, it is significant to make deep research and development on Software Radio.
This paper deals with the design and implementation of Digital Up Conversion and Digital Down Conversion based on the field-programmable gate array (FPGA). Firstly, the related theory of Digital Up Conversion, Digital Down Conversion and the foreground of FPGA are introduced. Then the development and implementation foreground are presented. Finally, the design and implementation of several important function modules are discussed in details. These modules are the numerically controlled oscillator(NCO), the decimating digital filter ,the pulse-shaping filter and the multiplierless interpolating digital filter. In these modules, the NCO module is introduced first combined with the algorithm look-up table (LUT) and Coordinate Rotation Digital Computer (CORDIC). Follow that the decimating digital filter including the cascade of cascade dintegrator-comb (CIC) filters and Half-Band filters (HBF) is introduced. Besides, second-order polynomials (ISOP) filter is used in order to compensate the CIC’spassband attenuation. In the end, the pulse-shaping filter with polyphase decomposition structure and the multiplierless interpolating digital filter consists of a sharpened CIC filter are discussed.
引文
[1] Kambiz C.Zangi R.David Koipillai.”Software Radio Issues in Cellular Base Stations” .IEEEJ.on Selected Area in Communication,1999, 17(4):561-573。
[2] 杨小牛,楼才义,徐建良.软件无线电原理与应用.第一版.北京:电子工业出版社,2001年。
[3] 杨小牛,邹少丞,楼才义.软件无线电技术与实现.北京:电子工业出版社。
[4] 刘凌,胡永生译.数字信号处理的FPGA实现.北京:清华大学出版社.2003。
[5] Y. Jang and S. Yang, “Non-recursive Cascaded Integrator-Comb Decimation Filters with Integer Multiple Factors,” 44th IEEE 2001 Midwest Symposium on Circuits and Systems, vol.1, Aug. 2001 Pages: 130 – 133.
[6] 丁玉美,高西全.数字信号处理.西安:西安电子科技大学出版社.1994。
[7] 王诚,薛小刚,钟信潮.Xilinx ISE5使用详解.北京:人民邮电出版社.2003年。
[8] 李涛,韩月秋.基于流水线CORDIC算法的三角函数发生器.电子技术应用.1999,(6).52-53。
[9] 李武翰.软件无线电接收机中可编程数字下变频器的研究与设计.大连理工大学硕士论文,2004年。
[10] 吴地金.无线通信中数字中频接收系统研究.浙江大学硕士论文,2004年。
[11] 李利,刘向东.软件数字下变频技术研究.电讯技术.2002,(5).pp27-28。
[12] Matthew P. Donadio . CIC Filter Introduction。
[13] Xilinx Datasheet .Cascaded Integrator-Comb (CIC) Filter V3.0。
[14] J. Kaiser and R. Hamming.“Sharpening the response of a symmetric nonrecursive filter by multiple use of the same filter”.IEEE Trans.Acoust., Speech, Signal Processing, vol. ASSP-25, pp. 415–422, Oct.1977。
[15] Alan N.Willson Jr.”A Programmable Interpolation Filter for Digital Communications Apllications”。
[16] J.S.Walther. “A unified algorithm for elementary functions” .in Proceedings of the Joint Spring Computer Conference, pp. 379–385, 1971。
[17] R.Andraka.”A survey of CORDIC algorithms for FPGA based computers”. in Proceedings of the 1998 ACM/SIGDA 6th international symposium on Field programmable gate arrays, Feb.1998, pp.191–200。
[18] 罗昀.中频数字化接受技术及系统实现.电子科技大学硕士论文,2004年。
[19] 张进,苏凯维.基于FPGA的数控振荡器的设计和实现.福州大学学报(自然科学版).2005,33(5).pp584-587。
[20] 汤伟良,李建东,李维英,杨军.数控振荡器在FPGA中的实现.微型机与应用.2003,11.pp23-25。
[2] 杨小牛,楼才义,徐建良.软件无线电原理与应用.第一版.北京:电子工业出版社,2001年。
[3] 杨小牛,邹少丞,楼才义.软件无线电技术与实现.北京:电子工业出版社。
[4] 刘凌,胡永生译.数字信号处理的FPGA实现.北京:清华大学出版社.2003。
[5] Y. Jang and S. Yang, “Non-recursive Cascaded Integrator-Comb Decimation Filters with Integer Multiple Factors,” 44th IEEE 2001 Midwest Symposium on Circuits and Systems, vol.1, Aug. 2001 Pages: 130 – 133.
[6] 丁玉美,高西全.数字信号处理.西安:西安电子科技大学出版社.1994。
[7] 王诚,薛小刚,钟信潮.Xilinx ISE5使用详解.北京:人民邮电出版社.2003年。
[8] 李涛,韩月秋.基于流水线CORDIC算法的三角函数发生器.电子技术应用.1999,(6).52-53。
[9] 李武翰.软件无线电接收机中可编程数字下变频器的研究与设计.大连理工大学硕士论文,2004年。
[10] 吴地金.无线通信中数字中频接收系统研究.浙江大学硕士论文,2004年。
[11] 李利,刘向东.软件数字下变频技术研究.电讯技术.2002,(5).pp27-28。
[12] Matthew P. Donadio . CIC Filter Introduction。
[13] Xilinx Datasheet .Cascaded Integrator-Comb (CIC) Filter V3.0。
[14] J. Kaiser and R. Hamming.“Sharpening the response of a symmetric nonrecursive filter by multiple use of the same filter”.IEEE Trans.Acoust., Speech, Signal Processing, vol. ASSP-25, pp. 415–422, Oct.1977。
[15] Alan N.Willson Jr.”A Programmable Interpolation Filter for Digital Communications Apllications”。
[16] J.S.Walther. “A unified algorithm for elementary functions” .in Proceedings of the Joint Spring Computer Conference, pp. 379–385, 1971。
[17] R.Andraka.”A survey of CORDIC algorithms for FPGA based computers”. in Proceedings of the 1998 ACM/SIGDA 6th international symposium on Field programmable gate arrays, Feb.1998, pp.191–200。
[18] 罗昀.中频数字化接受技术及系统实现.电子科技大学硕士论文,2004年。
[19] 张进,苏凯维.基于FPGA的数控振荡器的设计和实现.福州大学学报(自然科学版).2005,33(5).pp584-587。
[20] 汤伟良,李建东,李维英,杨军.数控振荡器在FPGA中的实现.微型机与应用.2003,11.pp23-25。