Then the several parts of the system , just as antenna , transmitter , receiver and base - band processing are researched one by one , especially , the key technologies of the system , as the tdas antenna of geo - leo link , mixer , local oscillator , demodulation and inspect technology , and benchmark demodulation technology are analyzed detailed 同时对星间链路的几大部分：天线、发射机、接收机、基带处理进行了研究，尤其是对geo - leo链路的tdas天线、混频器、本振、解调和检测技术、基准解调等关键技术进行了分析。
By using irm , heterodyne receiver with good image rejection and mmw - to - if once frequency conversion can be realized , which simplified receiver constitution prominently . the number of local oscillation ( lo ) sources is reduces and electromagnetic compatibility ( emc ) of mmw system is improved . also , the size , weight , power consume and cost of mmw receiver is reduced 采用毫米波镜频抑制混频器,可在保证镜频抑制性能的前提下,采用1次变频接收机,从而大大简化接收构成,减少本振数量,改善毫米波系统电磁兼容性,减小接收机体积、重量、功耗,并降低成本。
By making full use of favourable narrow - band tracing filter character of pll and by combining the merits of dds such as super fine frequency resolution 、 high frequency accuracy 、 very fast frequency hoping with it , the pll / pll + dds frequency synthesizer presents wide band high quality source and super small frequency hoping step . while the electronically tuned filter abates the image interference and notably improves the selectivity . the theorem of frequency synthesizer and center - frequency - fixed filter is simply but adequately introduced first in this paper 课题中所采用的pll或dds pll锁相频率合成方法充分发挥锁相环良好的窄带跟踪滤波特性，并结合dds的高频率分辨率、高频率精确度和高速频率捷变等优点，分别实现了系统所要求的高质量宽带本振源和小步长频率捷变；采用电调谐选频技术，则大大改善了接收机的选择性和抗干扰能力。
At first , the fundamental theories and realization methods of main parts of high purity frequency source in x band object simulator of vehicle - carried phased - array radar , such as phase - locked - loop , step recovery frequency multiplier , dielectric band - pass filter and micro strip band - pass filter are introduced in detail in this paper 本文一开始洲门针对机载相控阵雷达目标模拟器中的高纯本振源的实现，详细地介绍了琐相环、阶跃管倍频器、介质带通滤波器和微波带通滤波器的基本原理及其实现方法。
It mainly includes two parts : the frequency offset caused by the difference of the mobile equipment ’ s transmitting frequency and the nodeb ’ s receiving frequency ; the frequency offset caused by the vehicle of the mobile equipment , which is called doppler shift . accurate frequency offset estimation and compensation is of importance for demodulation 它主要由两部分构成:由于nodeb (基站)和移动台晶振本振频率的不同而产生频偏;由于移动台运动产生多普勒效应,引起的多普勒频偏,在信号功率谱上表现为多普勒频谱扩展(以后简称多普勒扩展) 。
Because the phase noise of the input crystal oscillator is excellent to 150dbc @ 10khz , we don ’ t adopt the pll method to yield the lo souce , but multiply the input signal . for to discard the harmonious frequencies yield by the multiplier , we have connected narrow - band filter between the circuit , and connected the isolator to reduce the interferes bring by the feedback signal of the amplifier . according to the frequency of the lo system , we aparted the whole lo system to two subsystems , and fixed in the different capsules 根据本振倍频系统的频率高低将整个倍频链系统划分为分为两条16 16的倍频链并用独立的腔体分开安装。另外,考虑到在ka频段进行三路功分很难保证三路本振信号等副等相,我们采取了在ku波段进行三功分,然后三路各自进行倍频至ka波段的方案。
In this system two oscillator are used for mixing . pll for high local oscillator and dds + pll for low local oscillator . by making full use of favourable narrow - band tracing filter character of pll and by combining the merits of dds such as super fine frequency resolution , high frequency accuracy , very fast frequency hoping with it , the pll / pll + dds frequency synthesizer presents wide band high quality source and super small frequency hoping step 系统采用两次混频，其中高本振的设计采用pll锁相环频率合成来实现，充分发挥了锁相环频率合成器的优良特性，实现了系统所要求的高质量宽频带本振源；低本振采用pll + dds频率合成来实现，结合pll优良的锁相特性与dds的高频率分辨率、高频率精确度等优点，实现了频率的小步进高精度合成。
Along with millimeter wave technology development , the high speed modulate 155mb / s millimeter wave receiver requires that the local oscilloscope performance should be excellent to satisfy its communication requirement . this article aimed at the requirement of 8mm millimeter wave receiver and developed a high performance millimeter yto frequency synthesizer . the article introduces several millimeter wave frequency synthesizers and analyzes their characteristic 随着毫米波技术的发展，在毫米波段高调制速率的毫米波通信机对毫米波本振源提出了更高的性能要求，本文针对8mm高速宽带155mb / s无线接入通信系统对毫米波本振源的要求，介绍了几种毫米波频综的设计方案，并进行了分析，最后决定采用锁相倍频的方案。
The major job is manufactured a transmitter , which has three upmixer channels . its function is to up convert the signals from c - band to ka - band . the input local oscillator is provided by a low frequency crystal oscillator which has a good performance of phase noise , through 512 times multiply to ka band . this sysetem is used in the laboratory as transmitter source of the fuze , for the multidimensional objects in practise , which lead to the complexity of the reflect signal , so the amplitude , frequency and the phase of the transmit signals both have a key role in dealing with the reflection signals . therefore , this system requires for both the coherence of the single channel ’ s amplitude , phase and multi channels 本文的主要工作是应用户要求制作一具有三发射通道的上变频系统,可以将c波段的微波信号上变频到ka波段的毫米波信号。系统的本振输入基频由一相位噪声非常好的低频率晶振提供,经过512次的倍频放大至ka波段。本系统作为实验室中引信的发射源,由于目标反射信号具有时变的多维性,反射信号变得极为复杂,在信号处理时,不仅信号幅值、频率有决定意义而且相位关系也很有决定意义。
