用于高清视频传输的405 MHz OFDM收发系统设计
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摘要
目前高清视频实时传输主要依赖于公共网络,专用视频传输方案在便携性、续航能力及传输距离上仍然有很大的提升空间。为满足远距离视频传输需求,本文系统采用OFDM技术,并从PA线性度、LNA噪声系数及阻抗匹配等角度展开分析,解决OFDM技术来带的高峰均比等问题。本文提出了一套载波为405 MHz的射频通信设计方案,采用i.MX6完成视频采集、压缩编解码与显示,FPGA进行基带数据处理,射频部分采用高性能、高可靠度AD9361作为核心器件。对关键参数进行仿真验证并绘制完整系统原理图及印刷电路板。经测试,该方案能够稳定传输高清视频,且总延迟为200 ms。
At present,the real-time transmission of high-definition video mainly depends on the public network,and the dedicated video transmission scheme still has a large room for improvement in portability,endurance and transmission distance. In order to meet the requirements of long-distance video transmission,the system adopts OFDM technology. The linearity of the power amplifier,the noise figure of the low noise amplifier and the impedance matching will be analyzed in this article to solve the problem of peak-to-average ratio of OFDM technology. A set of RF communication design scheme with405 MHz carrier is proposed. i.MX6 completes video acquisition,compression codec and display,FPGA performs baseband data processing,and the RF part adopts high performance and high reliability device AD9361. The key parameters have been verified by simulation. The test results on the fabricated PCB(Printed Circuit Board)indicate that the proposed scheme can stably transmit high-definition video and total delay is 200 ms.
At present,the real-time transmission of high-definition video mainly depends on the public network,and the dedicated video transmission scheme still has a large room for improvement in portability,endurance and transmission distance. In order to meet the requirements of long-distance video transmission,the system adopts OFDM technology. The linearity of the power amplifier,the noise figure of the low noise amplifier and the impedance matching will be analyzed in this article to solve the problem of peak-to-average ratio of OFDM technology. A set of RF communication design scheme with405 MHz carrier is proposed. i.MX6 completes video acquisition,compression codec and display,FPGA performs baseband data processing,and the RF part adopts high performance and high reliability device AD9361. The key parameters have been verified by simulation. The test results on the fabricated PCB(Printed Circuit Board)indicate that the proposed scheme can stably transmit high-definition video and total delay is 200 ms.
引文
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[2]陈崇森.基于i.MX6Q+FPGA平台Android下EIM总线接口设计[J].现代计算机,2016(13):60-65.
[3]姜浩,张治.基于AD9361的软件无线电平台设计与实现[J].电视技术,2015,39(15):51-54.
[4]刘崇.基于智能天线的UHF RFID阅读器中接收机的设计与实现[D].天津:天津工业大学,2014.
[5]伍颖,邓孟辉,匡代璋,等.高速PCB信号完整性分析及硬件系统设计中的应用分析[J].中国新通信,2018(5):121.
[6]阙志达,蔡佩芸,赖以威. MIMO-OFDM无线通信基带接收机设计[M].北京:机械工艺出版社,2014.
[7]Zhang C,Xiao Z,Gao B,et al. Power amplifier non-linearity treatment with distorted constellation estimation and demodulation for 60 GHz singlecarrier frequency-domain equalization transmission[J]. Iet Communi-cations,2014,8(3):278-286.
[8]聂朝辉.射频功率放大器线性化技术研究[D].成都:电子科技大学,2010.
[9]王双喜.基于前馈技术的高线性功率放大器设计[D].成都:电子科技大学,2012.
[10]毕查德拉扎维.射频微电子学:精编版[M].北京:机械工业出版社,2016.
[11]谢如元,徐加征,吴文力.印制电路板单端信号阻抗设计数值的理论分析[J].电子质量,2017(4):1-4.
[12]张淑艳,朱娟,王超,等.高速高阻抗模拟电路的印制电路板设计[J].计算机测量与控制,2013,21(11):3096-3097.
[13]张伟.传输线阻抗匹配问题浅析[J].电子制作,2016(20):21-21.
[14]宋燕辉,李丽,苏钢,等. 3G基站射频前端LNA阻抗匹配优化设计[J].微电子学与计算机,2012,29(12):180-183.
[15]莫里森,李献,等.接地与屏蔽技术:电路与干扰[M].北京:清华大学出版社,2016.
[16]Tamara Schmitz,Dave Ritter.用磁珠降低电源噪声[J].中国电子商情(基础电子),2010(6):68-69.
[17]栾鹏,梁法国,郑延秋.噪声系数主要测量方法及发展方向[C]//2013无线电、电离辐射计量与测试学术交流会,2013.