基于软件无线电的矢量信号生成软件设计及实现

发布时间：2018-05-10 09:30

本文选题：矢量信号发生 + 基带调制　；参考：《电子科技大学》2014年硕士论文

【摘要】：随着移动通信技术的高速发展,数字调制方式的日益丰富,硬件实现数字调制功能的复杂度和难度也日益提高,然而把调制解调功能用软件的方式来完成,极大地提高了通信系统设计的灵活性。同时缩短了工程的开发周期、降低了开发成本,并且具有较高的稳定性、易用性和可扩展性。如今在数字通信系统的测量和调试过程中,矢量信号发生器已被广泛应用,基带信号发生装置是矢量信号源中至关重要的部件,它为数字I/Q调制提供了相应的基带信号,同时其产生的数字调制基带信号也可以直接作为信号输出。本文设计不同调制类型的矢量基带信号通过通用软件无线电平台USRP2(Universal Software Radio Peripheral)上变频后发射。本文主要的研究内容如下:1、在用户自定义码源序列的基础上,对伪随机序列码源的生成技术进行了研究,提供了不同的伪随机序列码源选择,PN9、PN13、PN25等。2、基于I/Q调制原理对几种常规数字调制格式如MASK、MFSK、MPSK、MQAM等进行了分析研究,建立了码源信息与基带信号之间对应的星座映射关系,实现了多进制调制方式的基带信号调制输出,并实现了人为的叠加信道噪声,人为的加入I/Q畸变。3、对基带信号生成中的关键数字成型滤波技术进行了研究,成型滤波器主要减小了基带信号传输过程中的码间干扰,提高了频谱的利用率。在本文设计中直接调用LabVIEW里的升余弦滤波和FIR滤波等子vi来搭建基带信号成型滤波器,并通过MATLAB对滤波器成型效果进行了仿真验证。4、搭建测试平台,对设计进行了功能验证和信号质量测试,证实了本次设计的可行性。经过最终测试对比,基于软件无线电的数字调制基带信号可满足发生ASK、FSK、PSK、QAM等多种调制格式信号的需求,最高采样率可达20MS/s,最高符号率可达25MHz,通过对信号EVM和MER的分析验证,EVM值均小于6%,设计满足要求。
[Abstract]:With the rapid development of mobile communication technology and the increasingly rich digital modulation mode, the complexity and difficulty of realizing digital modulation function in hardware is increasing. However, the modulation and demodulation function is accomplished by software. The flexibility of communication system design is greatly improved. At the same time, it shortens the development cycle, reduces the development cost, and has high stability, ease of use and expansibility. In the process of measurement and debugging of digital communication system, vector signal generator has been widely used. Baseband signal generator is an important component of vector signal source, which provides the corresponding baseband signal for digital I / Q modulation. At the same time, the digital modulation baseband signal can also be directly output as the signal. In this paper, vector baseband signals of different modulation types are designed and transmitted by up-conversion of USRP2(Universal Software Radio Peripherals. The main contents of this paper are as follows: 1. On the basis of user-defined code source sequence, the generation technology of pseudorandom sequence code source is studied. Different pseudorandom sequence code source selection (PN9 / PN13 / PN25 et al. 2) is provided. Based on the principle of I / Q modulation, several conventional digital modulation formats, such as MASKN MFSKK MPSKN MQAM and so on, are analyzed and studied. The corresponding constellation mapping relationship between source information and baseband signal is established. The modulation output of baseband signal in multiary modulation mode is realized, and the artificial superposition channel noise is realized. The key digital shaping filtering technology in baseband signal generation is studied by adding I / Q distortion. The shaping filter mainly reduces the inter-symbol interference in the baseband signal transmission process and improves the utilization ratio of the spectrum. In this paper, the raised cosine filter and FIR filter are directly used in the design of LabVIEW to build the baseband signal shaping filter, and the shaping effect of the filter is simulated by MATLAB. Function verification and signal quality test are carried out to verify the feasibility of the design. Through the final test and comparison, the digital modulation baseband signal based on software radio can meet the needs of the signal with various modulation formats, such as ASK / FSK / PSKN QAM, etc. The highest sampling rate can reach 20 Ms / s and the highest symbol rate can reach 25 MHz. The analysis of signal EVM and MER shows that the value of EVM is less than 6 and the design meets the requirements.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM935

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