全数控短波接收机前端电路的设计与实现
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摘要
短波通信是指通过电离层的反射或折射后返回地面的电波传输的一种通信方式,被广泛应用于广播、导航和军事等领域。因为其具有抗摧毁能力强、设备简单、临时组网方便等特点,短波通信成为军事指挥作战的重要通信方式。然而,现代无线电通信的电磁环境越来越复杂,短波无线电通信设备大量增加,信号越来越拥挤,导致电台相互之间产生干扰,甚至产生阻塞而无法使用。因此,设计具有抗噪声、抗干扰、抗衰落、抗多径能力强且可以智能控制的短波接收机高中频前端电路,就显得特别急切。
本文首先通过分析几种常见接收机的结构、性能和优缺点,并结合课题所要求的频率分辨率、基准灵敏度、中频选择性、中频抑制比、镜频抑制比、阻塞、倒易混频和频率稳定度等主要技术指标确定了采用基于软件无线电的数字IF接收机结构。而本文的重点在于数字IF接收机的高中频前端电路部分。为了有效地提高镜频抑制比,混频电路的输出选择41.4MHz高中频；为了提高抗邻道干扰和阻塞干扰的能力,短波接收机前端电路中采用8组数控电调谐预选滤波器；为了有效提高中频抑制比,在混频之前,采用具有中频陷波点低通滤波器；为了提高系统的灵敏度,采用噪声系数很小的双栅场效应管3SK223设计低噪声放大器;为了减小组合频率的干扰,选择双平衡混频器ADE-1实现接收机前端的混频功能；为了增大增益受控动态范围,采用多级自动增益控制电路；为了实现高精度高稳定度的本振源及所要求的频率分辨率,采用单片机控制DDS芯片AD9953的方法设计本振,并采用高精度锁相倍频电路把高精度恒温晶振18.432MHz外部20倍频至368.64MHz作为AD9953的参考时钟源以减小相位噪声,采用跟踪滤波电路减小DDS固有的杂散信号,采用幅频均衡电路实现DDS输出信号的幅度平坦。
完成各个模块电路的设计、安装和调试,再按照给出的各项指标的测试方法测试模块电路的指标后,再对整个系统的各项指标进行测试,测试出的所有指标均达到课题要求。
Short-wave communication is a means of wave transmissions communication, which back to the ground by ionospheric reflection or reflection. It is widely applied to the field of broadcast, navigation, military affairs and so on. Because of the anti-jamming ability, simple equipment and easy for temporary networking, short-wave radio is the vital part in military operations. However, the electromagnetic environment is more and more complex, and short-wave radio communication equipments are increasing, so the short-wave signals become more and more crowded, which leads to radio disturbance among each other and even produces obstruction. Therefor, it is required to design the RF-IF circuit in the front-end of short-wave receiver which has characteristics such as anti-noise, anti-interference, anti-fading, anti-multipath ability and intelligent control.
Structure, performance, the advantages and disadvantages of several shortwave receivers are analyzed firstly in the paper. Based on the main technical indicators of short-wave receiver such as frequency resolution, insensitivity, IF selectivity, image rejection, IF recjection, blocking, reciprocal mixing and frequency stability, the digital IF receiver structure based on software radio is defined. And RF-IF circuit in the front-end of the digital IF receiver is discussed importantly in the paper. In order to improve the image rejection, the output of the mixer is designed to high-intermediate-frequency. In order to improve the ability of anti adjacent channel interference and blocking interference, the short-wave band is divided into eight bands, and each band is tuned and controlled by chip microcomputer. In order to improve the IF rejection, adopt a IF notch lowpass filter before the mixer. In order to improve the sensitivity of the system, employ a dual-gate FET3SK223whose noise figure is very low to design low noise amplifier. In order to reduce the interference of combination frequency, select double-balanced mixer ADE-1to complete the frequency conversion function. In oeder to increase the gain controlled dynamic range, use multi-stage automatic gain control circuits. In order to achieve high precision and high stability local oscillator whose frequency resolution is1Hz, direct digital synthesizer is choosed, and take some measures to improve the local oscillator performance, such as select oscillator368.64MHz which is produced by OCXO18.432MHz and external high-precision phase-locked multiplier with a factor of20as the reference oscillator to degrade the effects of phase noise of on-chip multiplier, employ the tracking filter to effectively eliminate the spurious signals and harmonics of sinusoidal waveform, Add gain control circuit controlled by frequency amplitude control word and DAC output to keep amplitude basically steady in required frequency range.
Each module is produced, installed and debugged, and then test the technical indicators of each module according to the given testing methods, and then test the various indicators of the system. All of the results of the short-wave receiver meet the subject requirements.
本文首先通过分析几种常见接收机的结构、性能和优缺点,并结合课题所要求的频率分辨率、基准灵敏度、中频选择性、中频抑制比、镜频抑制比、阻塞、倒易混频和频率稳定度等主要技术指标确定了采用基于软件无线电的数字IF接收机结构。而本文的重点在于数字IF接收机的高中频前端电路部分。为了有效地提高镜频抑制比,混频电路的输出选择41.4MHz高中频；为了提高抗邻道干扰和阻塞干扰的能力,短波接收机前端电路中采用8组数控电调谐预选滤波器；为了有效提高中频抑制比,在混频之前,采用具有中频陷波点低通滤波器；为了提高系统的灵敏度,采用噪声系数很小的双栅场效应管3SK223设计低噪声放大器;为了减小组合频率的干扰,选择双平衡混频器ADE-1实现接收机前端的混频功能；为了增大增益受控动态范围,采用多级自动增益控制电路；为了实现高精度高稳定度的本振源及所要求的频率分辨率,采用单片机控制DDS芯片AD9953的方法设计本振,并采用高精度锁相倍频电路把高精度恒温晶振18.432MHz外部20倍频至368.64MHz作为AD9953的参考时钟源以减小相位噪声,采用跟踪滤波电路减小DDS固有的杂散信号,采用幅频均衡电路实现DDS输出信号的幅度平坦。
完成各个模块电路的设计、安装和调试,再按照给出的各项指标的测试方法测试模块电路的指标后,再对整个系统的各项指标进行测试,测试出的所有指标均达到课题要求。
Short-wave communication is a means of wave transmissions communication, which back to the ground by ionospheric reflection or reflection. It is widely applied to the field of broadcast, navigation, military affairs and so on. Because of the anti-jamming ability, simple equipment and easy for temporary networking, short-wave radio is the vital part in military operations. However, the electromagnetic environment is more and more complex, and short-wave radio communication equipments are increasing, so the short-wave signals become more and more crowded, which leads to radio disturbance among each other and even produces obstruction. Therefor, it is required to design the RF-IF circuit in the front-end of short-wave receiver which has characteristics such as anti-noise, anti-interference, anti-fading, anti-multipath ability and intelligent control.
Structure, performance, the advantages and disadvantages of several shortwave receivers are analyzed firstly in the paper. Based on the main technical indicators of short-wave receiver such as frequency resolution, insensitivity, IF selectivity, image rejection, IF recjection, blocking, reciprocal mixing and frequency stability, the digital IF receiver structure based on software radio is defined. And RF-IF circuit in the front-end of the digital IF receiver is discussed importantly in the paper. In order to improve the image rejection, the output of the mixer is designed to high-intermediate-frequency. In order to improve the ability of anti adjacent channel interference and blocking interference, the short-wave band is divided into eight bands, and each band is tuned and controlled by chip microcomputer. In order to improve the IF rejection, adopt a IF notch lowpass filter before the mixer. In order to improve the sensitivity of the system, employ a dual-gate FET3SK223whose noise figure is very low to design low noise amplifier. In order to reduce the interference of combination frequency, select double-balanced mixer ADE-1to complete the frequency conversion function. In oeder to increase the gain controlled dynamic range, use multi-stage automatic gain control circuits. In order to achieve high precision and high stability local oscillator whose frequency resolution is1Hz, direct digital synthesizer is choosed, and take some measures to improve the local oscillator performance, such as select oscillator368.64MHz which is produced by OCXO18.432MHz and external high-precision phase-locked multiplier with a factor of20as the reference oscillator to degrade the effects of phase noise of on-chip multiplier, employ the tracking filter to effectively eliminate the spurious signals and harmonics of sinusoidal waveform, Add gain control circuit controlled by frequency amplitude control word and DAC output to keep amplitude basically steady in required frequency range.
Each module is produced, installed and debugged, and then test the technical indicators of each module according to the given testing methods, and then test the various indicators of the system. All of the results of the short-wave receiver meet the subject requirements.
引文
[1]熊年禄,唐存琛,李行健.电离层物理概论[M].武汉：武汉大学出版社,1999
[2]胡中豫.现代短波通信[M].北京：国防工业出版社,2003
[3]Pan xiaodong, Wei guanhui, Geng lifei,et al. Research on Electromagnetic Environment Effects for Typical Shortwave Communication Equipment[C],2011 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference,2011:303-306
[4]付贵华.基于短波电台的无线数据传输方案的设计与实现[D].哈尔滨：哈尔滨工业大学,2007
[5]Bruno M, Murdy M, Perreault P,et al. Tunable RF transceiver front for software-defined radio[C], Military Communications Conference,MILCOM 2009,2009:1-6
[6]谢金娟.短波接收机前端高中频电路的设计与实现[D].武汉：武汉理工大学,2010
[7]徐淑军.短波接收机射频前端电路设计与实现[D].大连：大连海事大学,2011
[8]唐静CPLD在短波接收机前端中的应用研究[D].武汉：武汉理工大学,2007
[9]Yan-kun Dong, Dong-ling Zhang, Lin-dong Ge.Algorithm of multi-signals separation for short-wave broadband receiver[C], Wireless Communications and Signal Processing,2011:1-5
[10]陈永泰,刘泉.通信电子线路原理与应用[M].北京：高等教育出版社,2011.8
[11]曹新星.短波接收机高精度本振信号源的设计与实现[D].武汉：武汉理工大学,2009
[12]Willcox D.E, Joonwan Kim, Loewen C,et al. Implementation of Digital Radio Modiale receiver-part I[C], System Theory,201042nd Southeastern Symposium on,2010:56-59
[13]Luiz Garcia Reis A, BarrosA.F, Gusso Lenzi K,et al. Introduction to the Software-defined Radio Approach[J], Latin America Transactions,IEEE, Vol.10,2012:1156-1161
[14]Deval Y, Deltimple N, Rivet F,et al.Low cost mobile RF terminal paradigms:From multi-radio to software radio[C], Solid-State and Integrated Circuit Technology,2010 10th IEEE International Conference on,2010:627-630
[15]Zhang Xuejing, Li Jinping, Zou Erning, et al. Study of Hardware Architecture Based on Software Radio[C], Information Technology and Application,2010:297-300
[16]陈国宇.大动态范围宽带接收机射频前端设计与实现[D].哈尔滨：哈尔滨工程大学,2007
[17]M.CHALLAL, A.AZRAR, H.BENTARZI,et al. On Low Noise Amplifier Design for Wireless Communication Systems [C], Information and Communnication Technologies:From Theory to Applications,2008:1-5
[18]周伟中VHF/UHF接收机的研究与设计[D].成都：西南交通大学,2010
[19]Asad A, Abidi. The Path to the Software-Defined Radio Receiver [J], IEEE JOURNAL OF SOLID-STATE CIRCUIT,2007(42):42-55
[20]陈永泰,陈景军,唐静,等.数控短波接收机高中频前端电路.中国.CN 102324946A[P].2012
[21]N. Garmendia, J. Portilla. Study of PM Noise and Noise Figure in Low Noise Amplifiers Working under Small and Large Signal Conditions [J], Microwave Symposium,2007. IEEE/MTT-S International,2007:2095-2098
[22]William F.Egan. Practical RF system design [M]. John Wiley & Sons, INC,2000
[23]胡小文.混频器的设计及其应用[J].计算机与网络,2003(21)：57-59
[24]张玉兴.射频模拟电路与系统[M].成都：电子科技大学出版社,2008-09-01,328-329
[25]刘宝玲,胡春静.通信电子线路[M].北京：北京邮电大学出版社.2005-01-01
[26]石雄.直接频率合成技术的研究与应用[D].武汉：华中科技大学,2007
[27]V.V. Romashov, L.V. Romashova. K.K. Khramov, Research of Phase Noise of Direct Digital Synthesizers[C].2011 International Siberian Conference on Control and Communications SIBCON,2011:168-171
[28]白居宪,直接数字频率合成[M].西安：西安交通大学出版社.2007.7
[29]K.J. Lin, C.M. Chang. Design of Direct Digital Frequency Synthesizers Based on Unilateral Second-Order Approximations[C],2011 IEEE 15th International Symposium on Consumer Electronics,2011:294-298
[30]Yi, Shu-Chung. A direct digital frequency synthesizer based on ROM free algorithm[J], AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS, 2010, vol.64(11):1068-1072
[31]Jouko Vankka. Direct Digital Synthesizers:Theory, Design and Applications[M]. Helsinki University of Technology,Department of Electrical and Communications Engineering, Electronic Circuit Design Laboratory.2000
[32]C. Meenakarn, A. Thananchayanont. A Sine-output ROM-less Direct Digital Frequency Synthesizer Using a Polynomial Approximation[C], The Proceedings of the 2003 Internaltional Symposium on Circuti and Systems,2003:625-628
[33]Tinery J.A Digital Frequency Synthesizer[J]. IEEE Trans.2004, AE-19(1):48-57
[34]Yongtai Chen, Mengya Liu, Changjin Sun. Design of Local Oscillator Based on DDS of High Performance Short-wave Receiver[C].The Second International Conference on Electric Information and Control Engineering,2012:314-317
[35]C. John Grebenkemper. Local Oscillator Phase Noise and its Effect on Receiver Performance [J],WJ Tech-note
[36]宦敏.宽覆盖、低杂散频率合成器的研制[D].成都：电子科技大学,2010
[37]AD9953 Datasheet, Analog Devices Inc,2003
[38]许朋,乔龙飞.高性能DDS芯片AD9954及其应用[J].电子元器件应用,201],Vol.13 No.2
[39]MSP430x15x, MSP430x16x, MSP430x161x Datasheet, Texas Instruments,2005
[40]黄建明.短波发射机高稳频率合成器的设计与实现[D].武汉：武汉理工大学,2010
[41]陈永泰,刘泉,唐静,钟小虎.采用CPLD设计的DDS短波发射机用频率合成源.中国.CN102201819A[P].2011.9.28
[2]胡中豫.现代短波通信[M].北京：国防工业出版社,2003
[3]Pan xiaodong, Wei guanhui, Geng lifei,et al. Research on Electromagnetic Environment Effects for Typical Shortwave Communication Equipment[C],2011 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference,2011:303-306
[4]付贵华.基于短波电台的无线数据传输方案的设计与实现[D].哈尔滨：哈尔滨工业大学,2007
[5]Bruno M, Murdy M, Perreault P,et al. Tunable RF transceiver front for software-defined radio[C], Military Communications Conference,MILCOM 2009,2009:1-6
[6]谢金娟.短波接收机前端高中频电路的设计与实现[D].武汉：武汉理工大学,2010
[7]徐淑军.短波接收机射频前端电路设计与实现[D].大连：大连海事大学,2011
[8]唐静CPLD在短波接收机前端中的应用研究[D].武汉：武汉理工大学,2007
[9]Yan-kun Dong, Dong-ling Zhang, Lin-dong Ge.Algorithm of multi-signals separation for short-wave broadband receiver[C], Wireless Communications and Signal Processing,2011:1-5
[10]陈永泰,刘泉.通信电子线路原理与应用[M].北京：高等教育出版社,2011.8
[11]曹新星.短波接收机高精度本振信号源的设计与实现[D].武汉：武汉理工大学,2009
[12]Willcox D.E, Joonwan Kim, Loewen C,et al. Implementation of Digital Radio Modiale receiver-part I[C], System Theory,201042nd Southeastern Symposium on,2010:56-59
[13]Luiz Garcia Reis A, BarrosA.F, Gusso Lenzi K,et al. Introduction to the Software-defined Radio Approach[J], Latin America Transactions,IEEE, Vol.10,2012:1156-1161
[14]Deval Y, Deltimple N, Rivet F,et al.Low cost mobile RF terminal paradigms:From multi-radio to software radio[C], Solid-State and Integrated Circuit Technology,2010 10th IEEE International Conference on,2010:627-630
[15]Zhang Xuejing, Li Jinping, Zou Erning, et al. Study of Hardware Architecture Based on Software Radio[C], Information Technology and Application,2010:297-300
[16]陈国宇.大动态范围宽带接收机射频前端设计与实现[D].哈尔滨：哈尔滨工程大学,2007
[17]M.CHALLAL, A.AZRAR, H.BENTARZI,et al. On Low Noise Amplifier Design for Wireless Communication Systems [C], Information and Communnication Technologies:From Theory to Applications,2008:1-5
[18]周伟中VHF/UHF接收机的研究与设计[D].成都：西南交通大学,2010
[19]Asad A, Abidi. The Path to the Software-Defined Radio Receiver [J], IEEE JOURNAL OF SOLID-STATE CIRCUIT,2007(42):42-55
[20]陈永泰,陈景军,唐静,等.数控短波接收机高中频前端电路.中国.CN 102324946A[P].2012
[21]N. Garmendia, J. Portilla. Study of PM Noise and Noise Figure in Low Noise Amplifiers Working under Small and Large Signal Conditions [J], Microwave Symposium,2007. IEEE/MTT-S International,2007:2095-2098
[22]William F.Egan. Practical RF system design [M]. John Wiley & Sons, INC,2000
[23]胡小文.混频器的设计及其应用[J].计算机与网络,2003(21)：57-59
[24]张玉兴.射频模拟电路与系统[M].成都：电子科技大学出版社,2008-09-01,328-329
[25]刘宝玲,胡春静.通信电子线路[M].北京：北京邮电大学出版社.2005-01-01
[26]石雄.直接频率合成技术的研究与应用[D].武汉：华中科技大学,2007
[27]V.V. Romashov, L.V. Romashova. K.K. Khramov, Research of Phase Noise of Direct Digital Synthesizers[C].2011 International Siberian Conference on Control and Communications SIBCON,2011:168-171
[28]白居宪,直接数字频率合成[M].西安：西安交通大学出版社.2007.7
[29]K.J. Lin, C.M. Chang. Design of Direct Digital Frequency Synthesizers Based on Unilateral Second-Order Approximations[C],2011 IEEE 15th International Symposium on Consumer Electronics,2011:294-298
[30]Yi, Shu-Chung. A direct digital frequency synthesizer based on ROM free algorithm[J], AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS, 2010, vol.64(11):1068-1072
[31]Jouko Vankka. Direct Digital Synthesizers:Theory, Design and Applications[M]. Helsinki University of Technology,Department of Electrical and Communications Engineering, Electronic Circuit Design Laboratory.2000
[32]C. Meenakarn, A. Thananchayanont. A Sine-output ROM-less Direct Digital Frequency Synthesizer Using a Polynomial Approximation[C], The Proceedings of the 2003 Internaltional Symposium on Circuti and Systems,2003:625-628
[33]Tinery J.A Digital Frequency Synthesizer[J]. IEEE Trans.2004, AE-19(1):48-57
[34]Yongtai Chen, Mengya Liu, Changjin Sun. Design of Local Oscillator Based on DDS of High Performance Short-wave Receiver[C].The Second International Conference on Electric Information and Control Engineering,2012:314-317
[35]C. John Grebenkemper. Local Oscillator Phase Noise and its Effect on Receiver Performance [J],WJ Tech-note
[36]宦敏.宽覆盖、低杂散频率合成器的研制[D].成都：电子科技大学,2010
[37]AD9953 Datasheet, Analog Devices Inc,2003
[38]许朋,乔龙飞.高性能DDS芯片AD9954及其应用[J].电子元器件应用,201],Vol.13 No.2
[39]MSP430x15x, MSP430x16x, MSP430x161x Datasheet, Texas Instruments,2005
[40]黄建明.短波发射机高稳频率合成器的设计与实现[D].武汉：武汉理工大学,2010
[41]陈永泰,刘泉,唐静,钟小虎.采用CPLD设计的DDS短波发射机用频率合成源.中国.CN102201819A[P].2011.9.28
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