Research of Generating Wideband I/Q Signal Based on AD9858

Many modulation and demodulation circuits need inphase and quadrature-phase(I/Q)signals.Traditionally,the methods of generating I/Q signals have many disadvantages.So DDS chip AD9858 of high-performance characteristics,produced by Analog Device Inc,is introduced in this paper.AD9858,as a core device,is adopted to generate 400MHz wideband I/Q signal by the control of FPGA.And the principles of generating I/Q signal,as well as designing and debugging circuit are also detailed in this paper.