A Design Of 8GHz-16GHz Small-scale Broadband Frequency Synthesizer

The frequency synthesizer is a key part of modern communication systems and electronic test systems, to provide a stable and reliable multiple local oscillator signal and the excitation signal for the system. Its performance has great influence on the entire system. With the development of wireless communications, people are seeking for the higher frequency output, the wider frequency range, the lower power supply and the smaller scale, which greatly contributed to the developme nt of frequency synthesis technology.This thesis is based on the basic principle of phase-locked loop. After the comparative analysis of several feasible options of the high- frequency wide-band frequency synthesizer, the bicyclic ring structure within a mixer is given to achieve the small-scale broadband frequency synthesizer system. The program uses the form of a large step loop output mixed with the feedback frequency of a small step loop, and ensures that the system phase noise and spurious suppression specifications by reasonable device selection and structure set up. One advantage of this scheme is using the locked loop voltage of the large step loop to supply the small step loop and preset the VCO output of the small step loop, which makes the small step loop output in the vicinity of the target frequency. This measure not only accelerates the lock process of the mixing loop, but also avoids the mistakes of the locking system. The entire design process includes optimization of the overall system design, circuit chip selection, simulation of various components of the loop, PCB board production, circuit control programming, physical production and debugging.After continuous debugging, the test results show that the system throughout the 8GHz to 16 GHz broadband enables 1MHz frequency step output and the spurious suppression is higher than 70 d Bc, the phase noise of 5.9895 GHz is better than-98.94dBc/Hz@10kHz,and the phase noise of 11.9790 GHz is better than-92.26dBc/Hz@10kHz, which meets the system specifications.