.3 ~ 16ghz Wide Coverage Of The Development Of The Frequency Synthesizer

Wide frequency-coverage synthesizer is popularly used in many domains,for example, it is can be found in Radar simulation system , such as its signal source and interference source. One disturbing problem in Wide frequency-coverage synthesizer is to make balance between its great variety of requirements, e.g. spurious level, phase noise level and output power flatness, in the present electronic system. Indeed, the complex frequency synthesizer, DDS+PLL, is considered as a main trend in correlative system. As the necessity of practical design, DDS is not implemented as a reference source to stimulate PLL. Because of it, invariable loop bandwidth is emphasized in such a PLL under the condition of wide frequency-coverage. A classical frequency synthesizer designing pattern, dual-PLL-switching, is proposed on the foundation of this theory. The benefit of this pattern makes the frequency-coverage of single PLL sub-system smaller in order to lower the difficulty of designing.In the dissertation, Radar simulation system is briefly introduced .Then the basic frequency synthesizer designing principle and it characteristics are in presentation and compared in detail. The spurious level and phase noise level in whole frequency system are analyzed in step. At the coming chapters of this dissertation, dual-PLL-switching plus frequency multiplier is implemented in this wide frequency-coverage frequency synthesizer for interference source in Rader simulation system, according to the index of this program. It provides a powerful demonstration with the feasibility of this scheme.In this thesis, dual-PLL-switching plus frequency multiplier provides a brief but efficient mean to realize the required frequency synthesizer. The results through practical test show a conclusion that the system is completely fit for the requirements especially on the key index, i.e. within its bandwidth of 3~16GHz, when the frequency step is 20MHz, the phase noise level is less than -83dBc/Hz @ 10kHz, the spurious level is below -60dBc and the output power is above 10dBm.In the final chapter, aiming at the deficiency of this design, some suggestion is proposed. Some certain designing methods and suggestion in this design also offer an efficient method for designing an ultra-wide frequency-coverage and fine frequency step synthesizer with good performances, meanwhile, it is also valuable for reference .