C-band Low Phase Noise Local Oscillator Developed

This subject comes from some project of military enterprise in Guizhou: The single pulse and examining direction receiver system. I undertake the Frequency Source(7-7.4GHz jumping and tuning frequency source)in this project. The integrative frequency synthesis technology of DDS+PLL+Mixer is adopted in the final scheme. The scheme is innovative and original not only in the technology but also in some module circuit. The hybrid frequency synthesis technology---DDS+PLL used in the subject have many advantages. Using this method, the merits of DDS such as super fine frequency resolution,high frequency accuracy,easy programmed can be in combination with the excellent character of narrow-band tracing filter merits of PLL. Thereby, the jumping and tuning function and specification of the system can be realized. At first,the basic theory and some question about the concrete design of the system on frequency synthesis,PLL,DDS,DDS+PLL are discussed. Following, the scheme of subject, the functional realization of each module, some questions which must be pay much attention in the system design, and the ultimate testing result of this subject is represented and analyzed in detail.