排序方式: 共有27条查询结果,搜索用时 187 毫秒
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Chen Yu Wang Gang Su Xiaobao 《电子科学学刊(英文版)》2014,(6):587-596
Traveling Wave Tubes(TWTs) are widely used in the radar and communications system as RF power amplifiers. A highly sophisticated power supply is required by TWT. In order to meet the severe requirements of Traveling Wave Tube Amplifier(TWTA), a novel two-stage topology high voltage converter for TWTA is proposed.The converter is based on Zero-Voltage Switching and Zero-Current Switching(ZVS/ZCS) resonant techniques. The high voltage converter operation principles are investigated and major features of the converter are discussed. The power switching mode of ZVS/ZCS is obtained. The experimental results show that the converter has good soft switching characteristics. Compared to the conventional hard switched Pulse Width Modulation(PWM) techniques, the high efficiency and low ripple of the converter for TWTA are realized. The efficiency of High Voltage Electronic Power Conditioners(HV-EPC) over 93.5% under the condition of 38~46 V input voltage and 260~300 W input power. The switching frequency of first-stage(preregulator) of HV-EPC is 89 k Hz and the switching frequency of second-stage(postregulator) is 44.5 k Hz. The highest output voltage of the HV-EPC is helix voltage which is about –6.8 kV. It is especially suitable for TWTA utilized in space satellite applications due to its high switching frequency and high power density. 相似文献
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电阻加载在宽带均衡器中的应用 总被引:1,自引:0,他引:1
给出了1种宽带的功率均衡器的快速设计方法。分析了均衡网络中加载电阻后谐振单元的谐振和耦合特性,并讨论了加载电阻对谐振单元品质因数的影响。对谐振单元的尺寸和电阻进行设定和调整,并使用仿真软件对级联网络进行优化,可以在短时间内设计出满足目标的均衡器。基于本方法,设计了2种频段的宽带功率均衡器。 相似文献
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针对螺旋线行波管的注-波互作用过程,依据等效线路模型和动力学方程,采用粒子模拟方法进行时域计算,并给出部分主要的数值求解结果。本文的仿真结果基本与现有软件的模拟结果一致,同时针对由于计算模型不同而产生的计算偏差,给出了深入的分析,为后续的研究工作奠定了重要的基础。 相似文献
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Ku波段模拟预失真线性化器 总被引:1,自引:0,他引:1
提出了一种基于模拟预失真方法的线性化器设计。利用预失真技术设计行波管配用线性化器的数学模型,得出了预失真电路的功率转移特性曲线和相位特性曲线。预失真电路采用上下支路对消结构,通过二极管产生失真信号,并利用2个可调衰减器和可调移相器来调节其幅度和相位,以此补偿功率放大器的AM-AM,AM-PM失真特性,改善输出信号的线性度。此外通过改变二极管的偏压,线性化器能够提供不同种幅度和相位特性的组合方式,用于不同特性的功放。基于该模拟预失真方法设计了行波管线性化器,在给定的动态范围内幅度扩张5 dB,相位扩张40°。 相似文献
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A. Franchi E. Colzi C. Elia R. A. Harris 《International Journal of Satellite Communications and Networking》1995,13(4):229-242
This paper analyses the performance of a coded orthogonal frequency division multiplexing (COFDM) based system for digital audio broadcasting using a highly inclined orbit satellite constellation. The sources of performance degradation considered are non-linear amplification in the satellite transponder and multipath propagation for mobile reception. Despite its strong peak-to-mean amplitude variation, COFDM has been found to be very robust against non-linear amplification. In the multipath channel, practical cases demonstrate low performance losses even in highly populated areas when highly inclined elliptical orbits (HEO) are used. 相似文献
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用于卫星转发器的高功率行波管放大器(TWTA)是非线性放大器,由于常工作在饱和状态导致非线性失真很严重.针对这种非线性变换特性,提出了一种基于神经网络的新的校正方法,主要步骤包括样本数据的预处理、网络结构的设计、采用LM算法进行网络训练,以及利用训练好的模型进行AM/PM或AM/AM校正等.通过仿真实验和对比分析表明,基于神经网络的校正方法优于传统校正方法,校正结果与真实值吻合程度高. 相似文献
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文章讨论了行波管放大器的非线性特性,研究了预失真和前馈线性化技术,提出一种利用预失真与前馈法相结合的新方法来对行波管进行线性化。最后用射频电路仿真软件ADS对预失真与前馈法相结合的方法进行仿真验证,得出仿真结果较好,对行波管线性化器的研究与实现有较大的参考和实用价值。 相似文献