【作者】 杨忠；

【导师】 耿相铭；

【作者基本信息】 上海交通大学 ， 电子与通信工程， 2012， 硕士

【摘要】 软件无线电是一种以现代通信理论为基础,以数字信号处理为核心,以微电子技术为支撑的无线通信体系结构[1][2]。可采用动态的软件编程对设备特性进行重配置,通过软件升级实现功能提高,是一种有效而且经济的解决方案。π/4-DQPSK作为线性窄带数字调制方式,相位跳变小,频谱特性相对于其他PSK有较明显的改善。可快速获得同步,具有抗快衰落及抗多径干扰的能力[3],在移动通信和卫星通信中得到了广泛应用。论文首先介绍了π/4-DQPSK技术的基本理论,着重说明π/4-DQPSK调制解调算法的原理及位同步实现的方法,并进行系统建模和原理仿真。接着设计一种基于低功耗DSP、CMX981、CMX992和CMX993组成的窄带无线通信系统。其中DSP实现信道编解码、同步提取及部分比特流处理等;CMX981实现低中频数字信号的滤波、抽取及内插等处理;CMX992和CMX993分别承担收发上下变频及射频放大等。系统由正交两路通道组成以提高频谱利用率,同时采用低电压工作,大幅降低系统功耗,适合便携式应用需求。更多还原

【Abstract】 Software Defined Radio (SDR) is wireless communication system which based on communication, digital signal processing and micro-electronics technology. The devices configuration can be realized by means of software, and the functionality can be improved through software upgrade. Software defined radio technology provides an efficient and comparatively inexpensive solution.π/4-DQPSK modulation is a linear narrowband technology which possesses features of high spectrum utilization ratio, better spectrum specification, stronger anti-fading and anti-jamming performance. So this modem method has been widely employed in mobile communication system, satellite communication system.Firstly, the features ofπ/4-DQPSK technology was introduced generally and modulation/demodulation theory, bit synchronization implement approach ofπ/4-DQPSK are depicted in detail, the result of simulation is given in these chapter. Then a new design of full-duplex narrowband communication system based on DSP, CMX981, CMX992, CMX993 is introduced. Channel codecs, bit-streaming processing and synchronous extracting which can be implemented in DSP. Data extraction/interpolation and filter can be realized by CMX981. Meanwhile, transceiver up/down conversion and radio frequency amplification can be realized by CMX992 and CMX993. The system has the characteristics of low power, high spectrum utilization ratio, and supports portable application.更多还原