介绍了直接数字频率合成（DDS）和直接正交上变频（DQUC）的基本原理，提出了基于DDS和DQUC的宽带多普勒频率模拟器设计方案，该方案在微波频段保持了DDS的所有优点，并抑制了在混频器中上变频时双边带中的无用边带。最后，介绍了基于AD9854和AD8346的直接正交上变频器优化设计的具体措施。并给出了实验结果。

The paper introduces the basic principles of direct digital synthesis(DDS) and direct quadrature up-conversion(DQUC).The realization method of a broadband Doppler frequency simulator based on DDS and DQUC Techniques is proposed,which has all advantages of DDS and offers an economic approach to frequency up-conversion.At last,the paper introduces several practical measures for direct quadrature up-converter optimization based on AD9854 and AD8346,and the experiment results are presented.

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