适用于短波跳频通信的改进型Delta-Sigma调制器
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摘要
针对短波通信中跳频技术(FHSS)的随机性、多频率性、瞬时性等特征,提出了一种适用于短波跳频通信的Delta-Sigma调制器,并用于构建频率自适应全数字发射机。在保留低频频谱特性的情况下,将优化过的低通Delta-Sigma调制器(LPDSM)与积分反馈(CIFB)拓扑结构级联,然后利用频率转换技术(FCT)进行变频操作,并根据载波频率实时调整带通(BP)DSM的调制度,调制器产生的高频数字信号将用于驱动高效开关功放。该改进型架构已经通过电路仿真验证,并在现场可编程门阵列(FPGA)中进行了实际电路的物理实现,为实现短波全数字发射机奠定了基础。
According to the characteristics of Frequency-Hopping Spread Spectrum(FHSS) in short-wave communications, such as the randomness, multi-frequency and transience, a Delta-Sigma Modulator(DSM) for short-wave frequency hopping communications is proposed and applied to build a frequency adaptive full digital transmitter. The optimized low-pass Delta-Sigma modulator(LPDSM) is cascaded with the integral feedback(CIFB) topology while preserving the low-frequency spectral characteristics. By using the frequency conversion techniques(FCT), the frequency-conversion operation is performed. The modulation-degree of the bandpass(BP) DSM is adjusted according to the carrier frequency in real time. The high frequency digital signal produced by the modulator will be used to drive a high-efficiency switching power amplifier. The improved architecture is verified by circuit simulation. The physical implementation of the circuit is completed in a field programmable gate array(FPGA). This work lays a foundation to implement all-digital short-wave transmitters.
According to the characteristics of Frequency-Hopping Spread Spectrum(FHSS) in short-wave communications, such as the randomness, multi-frequency and transience, a Delta-Sigma Modulator(DSM) for short-wave frequency hopping communications is proposed and applied to build a frequency adaptive full digital transmitter. The optimized low-pass Delta-Sigma modulator(LPDSM) is cascaded with the integral feedback(CIFB) topology while preserving the low-frequency spectral characteristics. By using the frequency conversion techniques(FCT), the frequency-conversion operation is performed. The modulation-degree of the bandpass(BP) DSM is adjusted according to the carrier frequency in real time. The high frequency digital signal produced by the modulator will be used to drive a high-efficiency switching power amplifier. The improved architecture is verified by circuit simulation. The physical implementation of the circuit is completed in a field programmable gate array(FPGA). This work lays a foundation to implement all-digital short-wave transmitters.
引文
[1]左卫.短波通信系统发展及关键技术综述[J].通信技术,2014(8):847-853.
[2]Hiorns R E,Sandler M B.Power digital to analogue conversion using pulse width modulation and digital signal processing[J].IEEE Proceedings G-Circuits,Devices and Systems,2002,140(5):329-338.
[3]Magrath A J,Clark I G,Sandler M B.Design and implementation of a FPGA sigma-delta power DAC[C]//Signal Processing Systems,1997.SIPS 97-Design and Implementation.1997 IEEE Workshop on.IEEE,1997:511-521.
[4]Jerng A,Sodini C G.A WidebandΔΣDigital-RFModulator for High Data Rate Transmitters[J].IEEEJournal of Solid-State Circuits,2007,42(8):1710-1722.
[5]Helaoui M,Hatami S,Negra R,et al.A Novel Architecture of Delta-Sigma Modulator Enabling All-Digital Multiband Multistandard RF Transmitters Design[J].IEEE Transactions on Circuits&Systems II Express Briefs,2008,55(11):1129-1133.
[6]Johnson T,Sobot R,Stapleton S.Manchester encoded bandpass sigma-delta modulation for RF class Damplifiers[J].Iet Circuits Devices&Systems,2007(1):21-26.
[7]Schreier R,Temes G C.Understanding Delta-Sigma Data Converters[M]//Understanding delta-sigma data converters.IEEE Press,2005:89.
[8]郝卜,叶焱,刘太君,等.带通Sigma-Delta数字调制器设计与仿真验证[J].数据通信,2016(6):25-28.
[9]Constantinides A G.Spectral transformations for digital filters[J].Proceedings of the Institution of Electrical Engineers,2010,117(8):1585-1590.
[10]刘小宁,谢宜壮,陈禾,等.多模式CORDIC算法结构改进与实现[J].电子学报,2018,46(2):495-500.
[2]Hiorns R E,Sandler M B.Power digital to analogue conversion using pulse width modulation and digital signal processing[J].IEEE Proceedings G-Circuits,Devices and Systems,2002,140(5):329-338.
[3]Magrath A J,Clark I G,Sandler M B.Design and implementation of a FPGA sigma-delta power DAC[C]//Signal Processing Systems,1997.SIPS 97-Design and Implementation.1997 IEEE Workshop on.IEEE,1997:511-521.
[4]Jerng A,Sodini C G.A WidebandΔΣDigital-RFModulator for High Data Rate Transmitters[J].IEEEJournal of Solid-State Circuits,2007,42(8):1710-1722.
[5]Helaoui M,Hatami S,Negra R,et al.A Novel Architecture of Delta-Sigma Modulator Enabling All-Digital Multiband Multistandard RF Transmitters Design[J].IEEE Transactions on Circuits&Systems II Express Briefs,2008,55(11):1129-1133.
[6]Johnson T,Sobot R,Stapleton S.Manchester encoded bandpass sigma-delta modulation for RF class Damplifiers[J].Iet Circuits Devices&Systems,2007(1):21-26.
[7]Schreier R,Temes G C.Understanding Delta-Sigma Data Converters[M]//Understanding delta-sigma data converters.IEEE Press,2005:89.
[8]郝卜,叶焱,刘太君,等.带通Sigma-Delta数字调制器设计与仿真验证[J].数据通信,2016(6):25-28.
[9]Constantinides A G.Spectral transformations for digital filters[J].Proceedings of the Institution of Electrical Engineers,2010,117(8):1585-1590.
[10]刘小宁,谢宜壮,陈禾,等.多模式CORDIC算法结构改进与实现[J].电子学报,2018,46(2):495-500.