一种适用于空间应用的高速调制系统的设计和实现

Design and Implementation of a High Speed Modulation System for Space Applications

为了适应空间科学技术的发展,满足空间科学应用系统的数据传输速率、多进制数字调制方式以及实现调制体制灵活性的要求,提出了一种适用于空间应用的高速调制系统的设计与实现方案.该方案采用了基于FPGA和DAC的通信调制技术,可在硬件设计不变的情况下,实现QPSK,8PSK和16QAM等多种调制方式下的高速数据传输.分析了高速调制在硬件实现上的技术难点,解决了高频率高精度同步时钟生成、高速数据转换、宽带调制等技术问题.实测表明,在载频为2 GHz时,该调制系统在8PSK调制下速率可达750 Mbit/s,且调制信号的矢量幅度误差(EVM)仅为3.3%.

To meet the requirements of high speed data transmission,multi-level modulation and the system flexibility in space applications,a modulation system design scheme was introduced,which has adopted the new techniques of the FPGA and DAC based communication system,and can be used for high speed data transmission with QPSK,8PSK,QAM or other kinds of digital modalation. The difficulties such as the high speed based-band signal conversion,wide-band modulation,carrier suppression,high frequency and high precision clock generation in the design and implementation of this modulation system are analyzed,and the solutions are also given.The test result shows that this modulation system can satisfy the performance requirements for most space applications.When the carrier frequency is 2 GHz,the transfer data rate of this modulation system with 8PSK modulation is up to 750 Mbit/s,while the EVM（Error Vector Magnitude） of the modulated signal is only 3.3%.