C波段卫星通信室外单元收发模块的研制

【作者】 梁东敏；

【导师】 杨涛；

【作者基本信息】 电子科技大学 ， 电磁场与微波技术， 2010， 硕士

【摘要】 卫星通信是现代最重要的通信手段之一,它有通信距离远,宽频带,信息容量大,稳定性好等优点,广泛应用于军事、导航、移动通信等领域。目前使用最广泛,稳定性最好的是C波段的卫星通信网。C波段的上行频率是6GHz,下行频率4GHz。卫星通信地面站的室外单元(ODU)收发前端电路是整个卫星通信系统的最重要组成部分。它性能直接影响到整个卫星链路通信的质量。本文在详细比较现代不同收发信机体系结构特点的基础上,结合课题指标完成了C波段卫星通信室外单元ODU收发前端电路的设计。所设计的接收机和发射机采用的都是是二次变频方案,共用一组频综单元,具有结构简单,性能优良,成本低,稳定性好等特点。实验测试结果表明所设计的发射机输出频率范围为5.8GHz~6.6GHz,输出功率(1dB压缩点)为+43dBm(20w),增益范围58.7~90dB,三阶交调抑制度43dB(1dB压缩点回退6dB状态下),杂散抑制优于67dBc。接收机工作频率范围3.4~4.2GHz,输出信号频率70MHz±18MHz,增益范围23.6dB~55.3dB,增益步进1dB,接收输出功率1dB压缩点为+15.4dBm,三阶交调抑制度优于54dBc(双载波输出功率0dBm状态下)。该接收机可以对卫星信标进行检波输出,从而可以实现在无频谱仪条件下辅助天线对星的功能,可以检测到的信标功率电平达-85dBm。本课题研究成果——ODU单元现已通过了国家无线电管理委员会的核准认证,并已装配于国内某机场的卫星地面站。在文章结尾,对当前的电路版本出现的问题进行了分析,并提出一些改进的建议,为后续电路的研制开发提供一些可借鉴的经验。更多还原

【Abstract】 Satellite communication is one of the most important modern communication forms. It has the advantages of far communication distance, wide frequency band, large information capacity, high stability and so on. It is widely applied in military, navigation, mobile communication. The C band, uplink on 6GHz and downlink on 4GHz, is the most widely used and stability communication network at present.The transceiver front-end of Satellite ground station out door unit (ODU) is the most important component part of satellite communication system. Its performance will directly affect the communication quality of satellite link. In this thesis, the advantages and disadvantages of the different modern transceivers are compared in detail. Then, the C band front-end circuits of satellite transceiver are designed according to the project specifications. The structure of the satellite transceiver is double conversion scheme based on the same local oscillators. The transceiver has the characters of simple structure, excellent performance, cheap cost and well stability.The test results indicate that the output power (1dB compress point) of the transmitter is 43dBm (20W) in the frequency rang from 5.8GHz to 6.6GHz. the gain rang is from 58.7 to 90dB. The three-order intermodulation (1dB compress point back off 6dB) and harmonic suppression is 43dB and 53dB respectively. The receiver works from 3.4GHz to 4.2GHz with gain rang from 23.6~55.3dB at 1dB step. The output power (1dB compress point) is +15.4dBm at 70MHz. three-orders intermodulation<-54dBc(dual carrier output power 0dBm). Using the detection of satellite beacon, direction alignment of the antenna is realized easily. The detection sensitivity of the satellite beacon is -85dBm. The ODU have authentication of State Radio Regulatory Commission. The ODU has been used in××airport.At the end, some improving advices are presented based on the experiment. All of these can provide important experiment for later research on this area.更多还原