空间高速光通信基带调制信号产生与相位同步方法研究

Baseband Modulation Signal Generation and Phase Synchronization Method of Space High Speed Optical Communication

高速调制基带信号的高质量产生与相位精确同步是实现空间光通信测距的关键技术。传统采用FPGA或数字信号处理器(DSP)与高速数模转换器(DAC)的实现方法,存在相位同步精度低、硬件实现复杂度高等缺点。该文提出一种高速光通信基带信号产生与相位同步方法,设计了相位闭环动态控制环路,通过实时调整高速信号发射时钟相位,可实现I,Q高速基带信号相位与外部参考时钟相位的确定性关系。实验结果表明:正交相移键控(QPSK)光调制信号码速率为5 Gbit/s时,相位同步精度小于2 ps,误差矢量幅度(EVM)小于8%;5 Gbit/s光通信速率误码率为10^(–7),接收灵敏度优于–47 dBm,测距精度优于2 mm。与传统方法相比,其灵敏度与测距精度均得到明显改善。

The high-quality generation and precise phase synchronization of high-speed modulated baseband signals are key technologies of space optical communication ranging system.Traditional approaches relying on FPGA or Digital Signal Processor(DSP)and high-speed Digital to Analog Convertor(DAC)technology often suffer from limited phase synchronization accuracy and high hardware complexity.A method for high-speed optical communication baseband signal generation and phase synchronization is proposed and a phase-locked dynamic control loop is designed in this paper.By dynamically adjusting the phase of the high-speed signal transmission clock in real time,the deterministic relationship between the I/Q high-speed baseband signal phase and the external reference clock phase can be achieved.The experimental results demonstrate impressive performance metrics:When the code rate of the Quadrature Phase Shift Keying(QPSK)optical modulated signal is 5 Gbit/s,the phase synchronization accuracy is less than 2 ps and the Error Vector Magnitude(EVM)is less than 8%;the bit error rate is 10~(–7)at a 5 Gbit/s optical communication rate,the receiver sensitivity is better than–47 dBm,and the ranging accuracy is better than 2 mm.Compared with traditional methods,both sensitivity and ranging accuracy are significantly improved.