.1.2 ~ 2.4 Ghz Synthesized Swept Source

This thesis originats from the Pre-research project of UESTC Testing Technology and Instrument Research Institute: 9 kHz ~ 2.9 GHz Spectrum Analyzer, of which 1.2 ~ 2.4 GHz Synthesis Sweeping Source is the first LO. As the core component of spectrum analyzer, the LO has a decisive bearing on the performance of the whole device. The purpose of this project is to design a wide frequence band, fine frequency step, low phase noise and low spur synthesis sweeping source suited for the spectrum analyser.This paper weighs, respectively, the advantages and disadvantages of the DDS+PPL frequency synthesis technology and the∑-△modulation fractiaonal PLL frequency synthesis technology in detail. Since the spectrum analyzer's LO calls for high spur performance, but relaively low frequency switching speed, the author finally chooses the∑-△modulation fractional PLL frequency synthesis technology as the project's scheme.Based on analysing technical indicators of synthesis sweeping source, the author puts forward a specific implementation plan, and demonstrated the feasibility of this scheme in detail. According to the implementation plan of the project, this paper details the design process of phase detector, loop filter, narrow pulse amplifier, loss of lock detecting circuit, control circuit and power module.This paper introduces the basic principles of fractional technology, and analyzes the cause of fractional spurious and the method of suppression. It focuses on the∑-△modulation noise shaping technology and the application of∑-△Modulation in fractional PLL, and describes the realization process of third-order∑-△modulator in the FPGA.The final test results serve as the evidence that the∑-△modulation fractional PLL frequency synthesis sweeping source can meet the project's requirements.