认知无线电系统捷变频信号源设计

根据信道环境自适应调节数据速率的需求，设计了一款高性能的认知无线电系统信号源。该信号源以直接数字频率合成芯片AD9854（DDS）为核心，现场可编程门阵列（FPGA）芯片EP1C6Q240作为控制单元，实现频率捷变和调制速率捷变以及具有双路正交输出的功能。经测试，频率精度、稳定度及杂散抑制均达到设计要求，并可集成于认知无线电通信设备中。

Design of a Cognitive Radio System Agile Frequency Signal Source

Aiming to the cognitive system need of opportunistic search for spectrum white space and switch of carrier frequency, as well as adaptive adjustment date rate to fit the channel environment, a high performance cognitive radio system signal source is designed employing AD9854 chip as a DDS core and EP1C6Q240 FPGA as a controller. This signal source features dual orthogonal outputs and function of agile adjustment of frequency and modulation rate. The test result indicates that the precision and stability of frequency as well as spurious suppression satisfy the design requirements. This unit can be integrated inside the CR communication equipments.