A new iterated decoding algorithm is proposed for differential frequency hopping (DFH) encoder concatenated with multi-frequency shift-key (MFSK) modulator. According to the character of the frequency hopping (FH) pat...A new iterated decoding algorithm is proposed for differential frequency hopping (DFH) encoder concatenated with multi-frequency shift-key (MFSK) modulator. According to the character of the frequency hopping (FH) pattern trellis produced by DFH function, maximum a posteriori (MAP) probability theory is applied to realize the iterate decoding of it. Further, the initial conditions for the new iterate algorithm based on MAP algorithm are modified for better performance. Finally, the simulation result compared with that from traditional algorithms shows good anti-interference performance.展开更多
In this paper,we examine the interrelation between innovation and commercial marketing using the DFH-4 series bus satellite as an example which customers are familiar with.Strategies in evolving satellite buses and ke...In this paper,we examine the interrelation between innovation and commercial marketing using the DFH-4 series bus satellite as an example which customers are familiar with.Strategies in evolving satellite buses and key subsystem technologies without compromising on advanced innovations,favorable heritage and thorough verification are also discussed.Market development experiences with the DFH-4 series bus satellite are summarized and market recognition is reflected from the space insurance perspective.展开更多
This paper describes the DFH-2A communications satellite which is the second generation of Chinese domestic communications satellites.From March 7,1988 to December 28,1991,China launched 4 DFH-2A satellites.They have ...This paper describes the DFH-2A communications satellite which is the second generation of Chinese domestic communications satellites.From March 7,1988 to December 28,1991,China launched 4 DFH-2A satellites.They have been used for CCTV’s and local TV’s programs transmission,domestic communications and broadcasting to foreign countries.展开更多
针对工程应用要求,采用软件无线电的体系结构,设计了一种具有宽带-软跳频特点的差分跳频通信系统方案。在现场可编程门阵列(FPGA)通用硬件平台上,采用Xilinx公司推出的用于数字信号处理的系统生成器(system generator for DSP)设计工具...针对工程应用要求,采用软件无线电的体系结构,设计了一种具有宽带-软跳频特点的差分跳频通信系统方案。在现场可编程门阵列(FPGA)通用硬件平台上,采用Xilinx公司推出的用于数字信号处理的系统生成器(system generator for DSP)设计工具,对系统的核心模块差分跳频信号处理器进行了建模设计,并仿真验证了方案的可行性和设计的正确性,对差分跳频通信系统的工程设计具有一定的参考价值。采用基于模型的设计方法,避开了传统基于HDL语言编程的设计方法,使整个设计工作更加简单、高效,大大缩短系统的开发周期,节约成本。展开更多
The 9th China International Aviation & Aerospace Exhibition (namely Airshow China or ZhuhaiAirshow) took place on November 13-18, 2012. As the only international aerospace trade show held in China, the fair provid...The 9th China International Aviation & Aerospace Exhibition (namely Airshow China or ZhuhaiAirshow) took place on November 13-18, 2012. As the only international aerospace trade show held in China, the fair provides valuable opportunities every even year for spacecraft and airplane manufacturers globally to exhibit their most advanced technologies, products and visions. Around 650 companies attended the event. During the one-week fair, a wide range of participants from展开更多
文摘A new iterated decoding algorithm is proposed for differential frequency hopping (DFH) encoder concatenated with multi-frequency shift-key (MFSK) modulator. According to the character of the frequency hopping (FH) pattern trellis produced by DFH function, maximum a posteriori (MAP) probability theory is applied to realize the iterate decoding of it. Further, the initial conditions for the new iterate algorithm based on MAP algorithm are modified for better performance. Finally, the simulation result compared with that from traditional algorithms shows good anti-interference performance.
文摘In this paper,we examine the interrelation between innovation and commercial marketing using the DFH-4 series bus satellite as an example which customers are familiar with.Strategies in evolving satellite buses and key subsystem technologies without compromising on advanced innovations,favorable heritage and thorough verification are also discussed.Market development experiences with the DFH-4 series bus satellite are summarized and market recognition is reflected from the space insurance perspective.
文摘This paper describes the DFH-2A communications satellite which is the second generation of Chinese domestic communications satellites.From March 7,1988 to December 28,1991,China launched 4 DFH-2A satellites.They have been used for CCTV’s and local TV’s programs transmission,domestic communications and broadcasting to foreign countries.
文摘针对工程应用要求,采用软件无线电的体系结构,设计了一种具有宽带-软跳频特点的差分跳频通信系统方案。在现场可编程门阵列(FPGA)通用硬件平台上,采用Xilinx公司推出的用于数字信号处理的系统生成器(system generator for DSP)设计工具,对系统的核心模块差分跳频信号处理器进行了建模设计,并仿真验证了方案的可行性和设计的正确性,对差分跳频通信系统的工程设计具有一定的参考价值。采用基于模型的设计方法,避开了传统基于HDL语言编程的设计方法,使整个设计工作更加简单、高效,大大缩短系统的开发周期,节约成本。
文摘The 9th China International Aviation & Aerospace Exhibition (namely Airshow China or ZhuhaiAirshow) took place on November 13-18, 2012. As the only international aerospace trade show held in China, the fair provides valuable opportunities every even year for spacecraft and airplane manufacturers globally to exhibit their most advanced technologies, products and visions. Around 650 companies attended the event. During the one-week fair, a wide range of participants from
