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设计了一种用于地面至卫星上行通信链路的高速光通信系统,系统采用可编程逻辑门器件(FPGA)作为主控单元,脉冲位置调制(PPM)作为基本调制方式,针对PPM通信中的帧同步问题,设计了特别的帧头帧尾结构保证信息同步。另外接收端对PPM信号同步解调时的时隙同步采用了四个相位时钟同步提取的方法,有效地降低了FPGA的工作频率,简化了系统设计。PPM编码采用格雷码映射,有效地降低了误比特率。系统最终实现了20Mbit/s的通信速率,实际测试误码率(BER)为8.9×10-9。该系统为后续星地间图像数据信息传输提供了实验支持。
A high-speed optical communication system for ground-to-satellite uplink communication link is designed. The system uses programmable logic gate device (FPGA) as the main control unit and pulse position modulation (PPM) as the basic modulation mode. For the PPM communication Frame synchronization problem, designed a special frame header frame structure to ensure information synchronization. In addition, the receiving end synchronously demodulates the time slot of the PPM signal by using four phase clock synchronization extraction method, which effectively reduces the operating frequency of the FPGA and simplifies the system design. PPM code using Gray code mapping, effectively reducing the bit error rate. The system finally achieved 20Mbit / s communication rate, the actual test bit error rate (BER) of 8.9 × 10-9. The system provides experimental support for the transmission of image data information between subsequent stars.