基于FPGA的USB测控系统中PM调制的研究与实现

PM modulation in the USB TT&C system based on FPGA

航天统一S波段(united S-band,USB)测控系统中相位调制(phase modulation,PM)是对遥控信息进行发送端调制的重要单元,针对航天测控PM调制载波频率高、采样速率大的需求,提出了一种基于现场可编程门阵列(field programmable gate array,FPGA)的USB测控系统中PM调制的研究方案及实现方法.设计将测距音信号与副载波信号联合调制到主载波,创新性地采用将高频分量与低频分量分解开、多路并行处理高速数字信号的方式实现相位调制.应用Modelsim仿真验证了设计的可行性,应用频谱仪分析频谱验证了设计的正确性,为地面遥控端提供了测试平台,在高速调制领域具有很强的可移植性.

PM modulation is an important unit to modulate the remote control information at the transmitter in the space USB TT&C(telemetry、track and command) system. Aiming at the requirement of high carrier frequency and high sampling rate of PM modulation in TT&C, this paper presents a research scheme and an implementation method of PM modulation in the USB TT&C system based on FPGA. The design combines the ranging-sound and the subcarrier signal to the main carrier, which realizes the phase modulation innovatively by separating the high frequency component and the low frequency component, and processing the high speed digital signal in parallel. The feasibility of the design is verified by Modelsim simulation, and the correctness is verified by spectrum analysis with spectrometer. The design provides a test platform for the ground remote control, which has strong portability in the field of high speed modulation.