水声多径单阵元主动时间反转检测性能研究

利用时间反转(Time Reversal,TR)良好的环境宽容性以及能量聚焦性,单阵元收发合置换能器通过主动时反信号对低信噪比下目标进行检测,以经典射线理论建立海洋中声多径信道传播模型,基于理论推导了单阵元主动TR信号目标检测的可行性.从理论上对单阵元收发合置换能器主动TR的处理增益进行详细分析,推导出单阵元主动TR的...     

应用Turbo乘积码的改进UWB判决反馈ATR接收机

针对超宽带(UWB)通信中数据辅助平均发射参考(ATR)接收机在判决错误较多时性能恶化的问题,提出了在相关器后串联Turbo乘积码(TPC)的译码器,取其译码判决输出来反馈更新相关模板,以降低判决错误数量的解决方案,据此形成了一种改进的应用TPC码的判决反馈ATR接收机.理论分析和IEEE CM3多径信道仿真结果表明:...     

基于TR069协议实现IPTV盒端管理

通过对IPTV机顶盒管理主要需求和TR069协议特点进行分析,给出了采用TR069协议实现IPTV机顶盒管理的实例化关键流程,对运营商实现IPTV机顶盒管理具有一定的参考价值。     

Statistical optimization of medium components affecting simultaneous fermentative hydrogen and ethanol production from crude glycerol by thermotolerant Klebsiella sp. TR17

A thermotolerant Klebsiella sp. TR17 for production of hydrogen from crude glycerol was investigated. Results from Plackett–Burman design indicated that the significant variables, which influenced hydrogen production, were KH₂PO₄ and NH₄Cl (for buffer capacity and nitrogen source). Subsequently, the two selected variables and crude glycerol were optimized by the Central Composite design for achieving maximum hydrogen and ethanol yield. The concentration of crude glycerol, KH₂PO₄, and NH₄Cl had an individual effect on both hydrogen and ethanol yield (p < 0.05), while KH₂PO₄ and NH₄Cl had an interactive effect on ethanol yield (p < 0.05). The optimum medium components were 11.14 g/L crude glycerol, 2.47 g/L KH₂PO₄, and 6.03 g/L NH₄Cl. The predicted maximum simultaneous hydrogen and ethanol yield were 0.27 mol H₂/mol glycerol and 0.63 mol EtOH/mol glycerol, respectively. Validation of the predicted optimal conditions exhibited similar hydrogen and ethanol yield of 0.26 mol H₂/mol glycerol and 0.58 mol EtOH/mol glycerol, respectively.     

TR组件发射波形畸变批次故障分析

在某批次收发组件(TR组件)随整机系统测试时,出现发射波形畸变故障现象.通过对该故障的分析,暴露出TR组件测试系统衰减器与整机测试系统的衰减器类型和衰减量不同,造成测试结果不一致;TR组件的相关检验文件只按技术协议要求施加标准激励,无静态测试,从而造成小信号输入产生自激的批次故障;TR组件所用功放在脉冲供电方式下防过冲措施不到位等3方面问题.     

Metric-Based and Angle-Rotated Tone Reservation Scheme for PAPR Reduction in OFDM Systems

High Peak-to-average power ratio （PAPR） has been a crucial problem in Orthogonal frequency divi- sion multiplexing （OFDM） systems. In all PAPR reduc- tion schemes, Tone reservation （TR） technology is consid- ered as one of the most promising methods because of no additional distortions no side information, and low imple- mentation cost. For conventional TR approaches, the as- signed value to reserved subcarriers just considers one peak value and this brings peak value up again easily. In this paper, a novel scheme named Metric-based angle-rotated （MBAR） for TR is presented. The scheme employs a met- ric to measure how much each subcarrier contributes to the output signal samples of large magnitude and then subcarriers with the largest positive metrics are selected to reduce PAPR. The simulation results show that when the reserved subcarriers number is 1.46 percent, the PAPR gain of the proposed method can achieve 0.4？dB at least at the probability of 10-3.     

基于多层PCB布线的Ku波段TR组件的设计

多层板布线技术作为一种重要的组件小型化的技术,应用越来越广泛,通过此技术,可以将TR组件的尺寸做到更小,重量更轻。文章介绍了多层PCB布线技术的相关知识,并利用此技术针对一个Ku波段的TR组件给出了相应的结构设计、电路设计和工艺设计,并最终测得发射端功率输出大于10W,杂散抑制40dB左右;接收端接收总增益大于100dB,噪声系数小于4dB。     

对流量测量不确定度评估中若干名词术语的看法

根据VIM(3rd)、JJF 1001-2011和JJF 1059.1-2012,对《ISO/TR 7066-1:1997 Assessment of uncertainty in calibration and use of flow measurement devices-Part1:Linear calibration relationships》、ISO 5168:2005和GB/T 29820.1-2013,对其中的若干术语、定义和符号作了初步分析,提出了一些不同看法和修改意见;分别对ISO/TR 7066-1和ISO 5168中关于“随机误差”、“系统误差”、“标准偏差和方差”;“不确定度和不确定度评定”、“重复性测量条件”,以及“灵敏度”和“线性校准方程”等定义和注解的表述进行了讨论。     

诺基亚2I BSC利旧的探讨

诺基亚2I的BSCTC与3I的TC单板类型相似,所以考虑可以通过改造将报废2IBSC的TC利用到现网。由于春节期间齐齐哈尔BSC部分A口话务负荷较高,但3IBSC设备已经无硬件可扩容,考虑到2I设备已报废,有闲置的TC硬件可以利旧。齐齐哈尔经过反复调测与实验,将2I设备TC利旧成功。     

应用传输参考信号改进的超宽带差分相关接收机

基于传输参考信号的思想，将其扩展到一组多个信号，提出了一种改进结构的超宽带（UWB）差分相关接收机，经过理论分析和UWB室内多径信道仿真表明，该方法检测性能优于传统的差分自相关法，在0～4m近距离时尤为突出，同时结构复杂度较低，便于实现。