Design Of X-band Wideband Frequency Synthesizer

As an important part of modern electronic communication systems,frequency synthesizers have been widely used in many fields such as communication,radar,electronic countermeasures and satellite navigation communication.In the wireless electronic communication system,the frequency synthesizer plays an important role as a core part of the radio frequency transceiver system.With the rapid development of modern electronic information technology,broadband telecommunication systems have become an important development trend,and the design of broadband frequency synthesizer is one of the important links to achieve broadband systems.In order to realize the broadband frequency synthesizer,and to ensure relatively good performance indicators,the design principle scheme to the realization of the physical circuit should be considered carefully.Therefore,designing a frequency synthesizer with broadband and satisfying certain phase noise,spurs and step frequency has important research significance.The research in this thesis is based on a local oscillator system project for a 6-18 GHz wideband receiver.The project requires the design of two frequency synthesizers.One is a broadband point frequency synthesizer with a frequency range of 3-8 GHz and the other is a wideband sweep frequency synthesizer with a sweep range of 6-12 GHz.The primary goal of achieving functionality is to further optimize for subsequent arrangements.Firstly,according to the working characteristics of the frequency synthesizer,the working principle of the phase-locked loop is studied.Secondly,according to the system principle of PLL,the architecture and key indicators of the frequency synthesizer based on PLL are analyzed,and two entity circuits and related control software programs of the frequency synthesizer are designed.The frequency synthesizer mainly consists of two parts: circuit and control.The circuit part mainly includes a power supply part,a phase locked loop part,and the like;the control part is mainly responsible for controlling the PLL chip.Finally,the designed frequency synthesizer function is tested.The wideband frequency synthesizer is capable of generating signals from 54 MHz to 13600 MHz,and the wideband sweep frequency synthesizer is capable of outputting wideband sweep signals of 6-12 GHz.Then the main performance parameters of the two frequency synthesizers are tested.The test results show that the design meets the requirements.