【作者】 陈惠兵；

【导师】 高勇； 刘高辉；

【作者基本信息】 西安理工大学 ， 电路与系统， 2006， 硕士

【摘要】 现代无线通信存在着体制繁多，电台难以互通的问题。传统的无线电接收机硬件依赖性强、信号适应能力差；软件无线电的出现导致了接收机技术的革新，其基本的思想是在同一硬件平台上，安装不同的软件，灵活地实现各种通信功能。 本文对软件无线电若干关键技术作了深入的分析，包括多速率信号处理技术、通信信号识别技术等。鉴于目前器件水平的限制，采用专用芯片构建了宽带中频数字化接收系统。 首先，阐述了软件无线电中频数字化接收系统实现的理论基础，包括基本采样定理、带通采样定理、信号抽取技术。然后，探讨了信号识别技术，在决策论方法基础上，提出了利用基于改进SOFM神经网络的方法对模拟调制信号进行自动识别。仿真结果表明，在信噪比较低的情况下，神经网络识别法识别率高于传统的决策论法的识别率，平均值高1.6个百分点左右，而对于信噪比较高的信号，表现出与传统的决策论法一样较高的识别成功率。接着，以调频信号的接收为例，选择了合适的软件无线电接收系统模型，介绍了接收系统的参数配置及其FM信号解调算法，并借助Matlab对接收系统工作过程作了仿真，得到了满意的仿真结果。最后，利用AD公司的AD转换器-AD6640、Intersil公司的数字下变频芯片-HSP50214B和闻亭公司的DSP开发板-C5410EVM开发板，组建了中频数字化接收硬件系统，验证了设计的软件无线电接收系统的正确性。更多还原

【Abstract】 Too many varieties of modulation schemes in modern wireless communication system make it hard for different systems to communicate with each other. Conventional receiver has high dependence on hardware and bad adaptability to signals. The emergence of software radio results in the renovation of receiver technology, whose basic idea is realizing every kind of communication function flexibly through installing different software in the same hardware platform.In this paper, some key technologies of software radio, including the multi-velocity signal processing, communicating signal recognition and so on, are researched deeply. Due to the limitation of devices, special chips are utilized to build the digital IF receiving system.Firstly, some basic theories in the realization of the IF digital receiving system of software radio are discussed in detail, including basic signal sampling theory, band pass signal sampling theory and extraction technique of the signals. Secondly, automatic recognition of the communication signals modulation is studied. A new recognition algorithm based on SOFM Neural Network is presented according to the decision-making method. Experimental results indicate that the recognition rate is 1.6 percent higher for low SNR signal and same well for high SNR signal by comparing Neural Network recognition method with conventional technology. Next, setting the FM signal receiving as an example, proper software radio receiving system is designed and the parameter configuration and signal of FM demodulation are introduced. The receiving process is simulated by Matlab and the satisfying results are acquired. Finally, AD6640 converter of AD company, HSP50214B digital down conversion chip of Intersil company and DSP evaluation board-C5410EVM of WenTing company have been used to build a system of software radio IF digital receiving system. The results validate the correctness of the designed software radio receiving system.更多还原