Design Of Low Phase Noise And Broadband Frequency Synthesizer

In nowadays' various communication systems, microwave measurement systems and monitoring systems, the frequency synthesizer's performance has a direct impact on the performance and quality of the system. With the increasingly demanding of engineers and researchers for communications equipment the research and development of the high-performance frequency synthesizer to provide the local oscillator signal and excitation systems and equipment, has a more practical engineering significance nowadays.According to design specifications, this article based on the basic principle of the PLL makes a comparative analysis of the various frequency synthesizer design, and determine to ?se the mixed interpolation in the bicyclic structure of the phase-locked loop synthesizer. According to this, we designed a wideband low phase noise frequency synthesizer. Then in accordance with the RF circuit common modular design, the whole system is divided into a plurality of modules, and described each specific module design and selection of devices, circuits in detail. After the description of the unavoidable mistake locking problems of phase-locked loop synthesizer plug mixer solutions, combined with the actual situation, we proposed the ?se of the phase detector instead of the N divider method. Throughout the design process includes testing the overall system design, chip selection, design and simulation associated circuitry, PCB board production, programming and final chip control circuit.After continuous debugging, the test results show that the system throughout the 2GHz to 8GHz broadband enables 20 MHz frequency step output and the spurious suppression is higher than 70 dBc, the phase noise of 8GHz is better than-110 d Bc/Hz@10kHz, which meets the system specifications...