天地一体化超视距雷达的激励源设计

针对单通道天地一体化超视距雷达不能多站组网的问题，设计了一种新型的激励源系统。系统利用现场可编程门阵列（FPGA）和通用串行总线（USB）实现多路发射通道控制，并通过直接数字式频率合成器（DDS）产生初始相位周期变化的线性调频波。理论分析表明，回波信号经过两次频谱变换能产生特定的多普勒频移，从而在多普勒频谱上被展开，实现信号多发一收。实验结果验证了激励源设计的可行性，可用于多站同步观测。

Design of an excitation source for sky-surface wave hybrid radars

Since a sky-surface wave hybrid radar with single channel is unable to achieve multi-station networking operation,a new type of excitation source system is designed to tackle this issue. To accomplish multiplexed channel control,the system utilizes field programmable gate array (FPGA) and universal serial bus(USB) for multiplexed channel control. Moreover,it generates the linear frequency modulated wave whose initial phase period changes through a direct digital frequency synthesizer (DDS). Theoretical analysis demonstrates that the echo signal can generate a specific Doppler shift by two spectral transformations,which is accordingly unfolded on the Doppler spectrum. Consequently,the multiple transmission with single received approach is realized due to the design. The feasibility of the excitation source design is verified by the experimental results and so it can be applied in multi - station synchronous observation.