The paper proposed the research and implement of text similarity system based on power spectrum analysis. It is not difficult to imagine that the signals of brain are closely linked with writing process. So we build t...The paper proposed the research and implement of text similarity system based on power spectrum analysis. It is not difficult to imagine that the signals of brain are closely linked with writing process. So we build text modeling and set pulse signal function to get the power spectrum of the text. The specific detail is getting power spectrum from economic field to build spectral library, and then using the method of power spectrum matching algorithm to judge whether the test text belonged to the economic field. The method made text similarity system finish the function of text intelligent classification efficiently and accurately.展开更多
为满足高功率微波技术对信号相位差测量的应用需求,设计一种微波脉冲鉴相器,实现X波段脉冲信号相位差的准确测量。鉴相器基于I/Q解调原理,采用无需外加电源供电的双平衡电路结构,以微带电路的形式设计同相功分器和分支线电桥,结合贴片...为满足高功率微波技术对信号相位差测量的应用需求,设计一种微波脉冲鉴相器,实现X波段脉冲信号相位差的准确测量。鉴相器基于I/Q解调原理,采用无需外加电源供电的双平衡电路结构,以微带电路的形式设计同相功分器和分支线电桥,结合贴片式混频器将两路待测信号进行正交混频,得到与待测相位差相关的电脉冲。电路设计中采用宽带电路结构,扩展使用带宽;结合全电磁仿真对各信号传输通路的相位一致性进行分析计算,避免电路出现初相误差;采用低通滤波器滤除高次谐波干扰,提高鉴相准确度,最后制作实物样机并进行性能测试。测试结果表明,该鉴相器能够实现百纳秒级微波脉冲信号的相位测量,动态范围达到10 d B,最大承受功率22 d Bm,测量误差<5°。展开更多
文摘The paper proposed the research and implement of text similarity system based on power spectrum analysis. It is not difficult to imagine that the signals of brain are closely linked with writing process. So we build text modeling and set pulse signal function to get the power spectrum of the text. The specific detail is getting power spectrum from economic field to build spectral library, and then using the method of power spectrum matching algorithm to judge whether the test text belonged to the economic field. The method made text similarity system finish the function of text intelligent classification efficiently and accurately.
文摘为满足高功率微波技术对信号相位差测量的应用需求,设计一种微波脉冲鉴相器,实现X波段脉冲信号相位差的准确测量。鉴相器基于I/Q解调原理,采用无需外加电源供电的双平衡电路结构,以微带电路的形式设计同相功分器和分支线电桥,结合贴片式混频器将两路待测信号进行正交混频,得到与待测相位差相关的电脉冲。电路设计中采用宽带电路结构,扩展使用带宽;结合全电磁仿真对各信号传输通路的相位一致性进行分析计算,避免电路出现初相误差;采用低通滤波器滤除高次谐波干扰,提高鉴相准确度,最后制作实物样机并进行性能测试。测试结果表明,该鉴相器能够实现百纳秒级微波脉冲信号的相位测量,动态范围达到10 d B,最大承受功率22 d Bm,测量误差<5°。
