近距离无线电台邻道干扰的功率谱解析

指挥控制系统的无线通信设备数量多、工作频率范围窄,相互之间存在严重的邻道干扰.针对近距离电台间邻道干扰问题,提出了基于功率谱解析的分析方法.首先理论推导了信号原功率谱密度函数与展宽延拓后功率谱密度的严格数学关系,在此基础上研究邻道干扰产生机制,进而分析不同邻道的干扰强度,得到了邻道功率与频率之间的关系式,推导了进入接收机的信干噪比(SINR);最后,通过仿真验证了所提出的分析方法的可行性.理论计算与仿真结果相差在0.5 dB以内,为进一步有效规划指控系统频谱和提高利用效率提供了重要依据.     

数字预失真功放EVM特性分析与实验验证

推导了无线通信系统误差向量幅度(EVM)与邻道功率比(ACPR)指标的相互关系,得出了通过功放线性化改善ACPR使得系统EVM减小的结论。随后采用具备结构简单、处理速度快、实时性好等优点的查找表(LUT)方法设计数字预失真器(DPD),数字预失真器用FPGA方式实现。对该数字预失真器进行了仿真分析,验证了理论推导结论,最后给出DPD功率放大器试验测试数据,与仿真结果吻合良好。     

考虑邻道干扰条件下的Ad Hoc网络性能分析及优化

根据邻道干扰(Adjacent-channel interference, ACI)问题对网络性能的影响,本文首先提出了一种面向连续相位频移键控(Continuous-phase frequency-shift keying, CPFSK)和跳频的Ad Hoc网络的性能分析方法。此分析方法有效解释了Nakagami衰落、阴影、CPFSK调制因子、信道数目、码速率、干扰源空间分布、部分带内功率等因素对网络性能的影响,并给出了中断概率和传输容量的数学表达式。此外,基于上述分析结果,使用Nelder-Mead单纯形方法对Ad hoc网络传输容量性能进行优化。最后,仿真结果给出了网络传输容量最大化条件下的参数最优配置,验证了本文所提Ad Hoc网络分析方法的有效性。     

硅基OLED数字型像素驱动电路MOS管尺寸对数据写入的影响

以传统的6T SRAM(5T+1MOS驱动管)结构硅基OLED像素电路为例,分析了开关管尺寸对数据写入的影响.提出了一种新型数字型硅基OLED像素电路,用5T(4T+1MOS驱动管)实现与6T SRAM(5T+1MOS驱动管)结构相同的功能.另外新型的像素电路与传统的SRAM结构相比,其数据写入不受开关管尺寸的影响,可...     

尺寸分布优化的硅基纳米材料的制备及其光致发光特性研究

纳米材料尺度的均匀性分布是保证纳米硅材料高效发光的基本要求,而纳米材料尺度分布的不均匀性却是纳米硅材料制备过程中的常见问题.在激光烧蚀沉积纳米硅材料中采用挡板技术和背散射技术提高了材料的尺度分布的均匀性,减少了材料表面的大颗粒,有效改善了材料的发光特性,使材料的发光强度提高,且发光峰的半峰宽变窄.     

小型化功率放大模块

介绍了ＶＨＦ频段小型化功率放大模块的设计方法和试验研制过程,采用混合集成电路技术,将两级芯片集成到微型封装的密封管壳中,采用内匹配技术,实现阻抗匹配,提高和改善增益。在 １３０～１８０ＭＨｚ率范围内,试制出Ｇｐ≥３０ｄＢ,Ｐｏ≥１．５Ｗ,л≥５０％的功率放大模块。功率放大模块的体积为１５ｍｍｘ１０ｍｍｘ５ｍｍ,其质量只有 ３克。     

UHF大功率功放模块设计的新方法

针对OFDM信号对功放高峰值功率的要求,提出了工作在220～400 MHz的大功率功放模块设计的新方法.该方法结合ADS软件仿真分析,按仿真模型用QFX86射频同轴电缆自制了功率分配/合成网络,用该网络设计了一款输出峰值功率不小于300W的功放模块.该模块已成功应用于某电台中且工作良好.     

电力半导体模块新趋势

简要叙述了电力半导体模块的发展过程,介绍了晶闸管智能模块的结构和特性,描述了IGBT智能模块的现状和发展趋势,指出了我国大力发展IPEM的必要性.     

基于列车监测网络设备的射频功放模块设计

列车关键设备及行车状态的无线实时监测是列车安全运行的有效技术保障,而如何延长无线监测节点通信距离、增强通信可靠性成为研究重点。本文提出适用于列车监测特殊环境的射频功放模块设计方法,采用集成化芯片RF5110G避免内部干扰,通过滤波电路和阻抗匹配优化电路板设计,所设计的功放模块很好地解决了列车特殊环境导致的信号衰减问题,增强了监测网络节点数据传输可靠性,为列车监测、维护提供了可行的方法。     

高效低成本的硅双极GSM双频PA模块

提出了在单个陶瓷基底上利用硅射频Ic双极芯片技术设计PA模块的方法和测试数据.得到的数据表明利用硅技术生产出的产品性能可与现有GaAs技术产品相媲美.     

相邻信道捣抑制和相邻信道干扰对802.11 WLAN性能造成的影响

随着无线联网技术以及其他无线技术在无许可限制的同一频谱范围内的迅速推广应用,Wi-Fi(R)(802.11)产品遭受的射频(RF)干扰越来越多,已严重影响了无线局域网(WLAN)的数据吞吐性能.本文分析了相邻信道干扰(ACI)的来源以及射频设计实践,通过此实践可以改善WLAN的相邻信道抑制(ACR)从而全面提高其性能.     

1.3 mu m semiconductor laser power amplifier

The performance of a 3.4-Gb/s system using a low-power 1.318- mu m distributed-feedback (DFB) laser transmitter and a traveling-wave semiconductor laser power amplifier is studied. The -14.5-dBm, input from a directly modulated DFB laser is boosted to +10.3 dBm, of which +4.8 dBm is coupled into the transmission fiber. The penalty, caused by amplifier noise and pattern effects due to gain saturation, is less than 0.5 dB.<>     

GaAs FET power amplifier module with high efficiency

A high-efficiency GaAs FET power amplifier having a total efficiency of 70% and an output power of 2 W is realised in the 900 MHz band. A drain efficiency of 80% was achieved at a low operation voltage of 6 V. These high efficiencies were obtained by using the even-order harmonic tuning of an output matching circuit. Important parameters for achieving this efficiency are also clarified.     

Medium power 12?18 GHz amplifier module

Broadband Ku-band amplification has been extended into the range of medium power levels. A single-ended 100 mW amplifier stage has been developed for the 12?18 GHz frequency band using a GaAs Schottky-barrier field-effect transistor. Minimum gain at 20 dBm of output power was 4dB. When operating in the driver mode, a minimum gain of 5dB at an output power of 15 dBm was measured across Ku-band. Higher gains can easily be achieved by cascading several of these amplifier stages. Gain, output power and impedance characteristics as a function of frequency are discussed.     

Electrical characteristics of single-gate interference transistors based on various semiconductor materials

The current-voltage and high-frequency characteristics of single-gate interference T transistors based on quantum wires made of various semiconductors, specifically, Si, Ge, GaAs, InAs, GaSb, InSb, GaP, and InP, were studied theoretically. Two scattering mechanisms were taken into account in the T-transistor model in order to assess their effect on the electrical characteristics of devices. The adequacy of the suggested model was verified by comparing the results of simulation with experimental data. The calculations were performed using the QW-NANODEV subsystem for simulating the devices based on quantum wires.