.4-8ghz Broadband Dds Phase-locked Swept Source Development

The subject derives from the project of "4 ~ 8GHz spectrum analyzer", which is collaborated with TianJin ZhongYuan instrument and equipment Inc., and UESTC (University of Electronic Science and Technology of China) undertake the 4~8GHz Wideband Sweep Source in this project. The integrative frequency synthesis technology of DDS+PLL+Douber+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 thesubject 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 wideband sweep function and specification of the system can be realized.The principle of sweep source is introduced at first in this paper. Subsequently, the basic theory and some question about the concrete design of the system on frequency synthesis^ PLL^ DDS> DDS + PLL are discussed. And then some contents about Microwave Solid-State Source which is related to the subject are introduced. At last, 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.