Application of image frequency based on AD9912

Conventional DDS can't synthesize a frequency beyond the 1/2 frequency of sampling clock,which restricts the applications of the DDS device.In the analysis of DDS output signal in practical application,besides the design frequency,there are still some image frequencies belong to UHF band,And there is a good linear relationship between this two kinds of frequencies.So it provides a way to calculate the image frequencies and get them by filtering.To expand the applications of the DDS device,this paper proposes a method of UHF frequency synthesis which makes use of image frequency.A frequency synthesis system was designed and the corresponding control codes were programmed as well.Achieved the requirement of synthesizing a 1 500 MHz UHF signal by DDS device.