基于FPGA的FM信号发生器设计与实现

摘要

In order to improve the frequency accuracy and stability of the FM signal generator,and make it relevant technical parameters adjustable,a method is designed based on FPGA and Direct Digital Synthesizer(DDS)technol⁃ogy. The system achieves adjustable FM signal modulation parameters by the PC,and through the PCIE interfaceFM signal control word is transferred to the FPGA,FPGA controls the integrated DDS core to achieve the FM signal gen⁃eration. Test results show that the frequency of FM signal has high frequency accuracy and stability,the maximum output of the carrier frequency can reach 40 MHz,and the amplitude accuracy can reach 5 mV. The FM signal gener⁃ator has a broad application space in software radio,radar target feature identification and radar detection distance and other fields.%为提高FM信号发生器的频率准确度和稳定度，并使其相关技术参数可调，设计了一种基于FPGA和直接数字频率合成（DDS）技术的产生方法。系统通过上位机设置FM信号的调制参数，通过PCIE接口将上位机设置的FM信号控制字传给FPGA，FPGA内部通过控制DDS核来实现FM信号的产生。测试结果表明，FM信号的频率精度高且稳定性好，最高输出载波频率达40 MHz，幅度精度能达到5 mV。该FM信号发生器在软件无线电、雷达目标特征识别和雷达距离探测等领域具有广阔的应用空间。