直接频率合成器双路上变频信号产生方法

摘要

针对DDS芯片抗辐照特性不强,以及利用FPGA控制内置ROM读表法中FPGA内置ROM存贮量有限,产生不了时宽长线性调频信号等问题,提出一种基于FPGA的DDS上变频I、Q双路基带线性调频信号产生方法以简化硬件设计.该方法根据DDS原理产生I、Q双路基带线性调频信号,利用乘法器分别与要达到的变频信号的中心频率相乘并通过加法器求和,根据三角公式中的合差化积原理,产生所需的线性调频信号,再经混频器上到射频,实现发射信号的调制.仿真结果表明:该方法产生的调频信号从时域和频域均满足工程化要求,有效地简化了调频信号源硬件设计.%In this paper, a liner FM signal generation methods was proposed based on DDS up-converted frequency I/Q twin-channel base band of FPGA to simplify the hardware design, because anti-radiation characteristics of the DDS chip was not strong,and FPGA built-in ROM storage capacity was limited and could not produce the wide long-term FM signals by using FPGA control the build-in ROM to read the data form. The generation methods could realize the signal modulatioa According to the principle of DDS, the I/Q twin-channel liner FM signal was generated, then multiplied with the center frequency to be achieved Then based the principle of co-differential of trigonometric formulas, the required liner FM signal was generated and transmitted to RF signal. The simulation result showed that the generated FM signal met the engineering requirements of both time and frequency, also effectively simplified the hardware design of the FM signal generator.