The Design And Implementation Of The Type-XX Miniature Low-power High-speed Hopping Frequency Source

As a kind of key equipment, the frequency synthesizer plays a decisive role in the performance of electronic system. With the rapid development of the electronic technology, weapon guidance, Radar, mobile communications, electronic warfare and electronic measuring instruments in the present require the higher performance of electronic system, the development and application of the frequency synthesizer have played critical roles in various parts of the world and field. Fast hopping, low phase noise, high spurious rejection, high frequency resolution, wide bandwidth have become the hot research spot in all countries.In this article, the PLL frequency source with the advantages of miniaturization, low power consumption, high speed frequency hopping are studied. It lays special stress on analyzing the main factors of products’ capability as follows: two single PLL circuits cause crosstalk between signals on the miniaturization four layer circuit board, the increased peripheral device and routing problem caused by two single PLL circuits, optimization distribution of the power consumption, the design method of low phase noise, the realization of fast frequency hopping. Some innovative applications to solve the problems mentioned above are introduced: the technology of variable bandwidth using PLL software, the hardware fractional-N technology, the electromagnetic compatibility design of multiple signal and DC-DC power supply to prevent interference, in order to gain the optimum procedure of the frequency source and the optimized placement of PLL circuit design.Firstly, it gives detailed instructions on the principle and main components of the PLL circuit, then it gives analysis and inference in details of the design methods’ selection, which can realize miniaturization, low power consumption, high speed frequency hopping at the same time. Finally, the design of indirect frequency synthesis becomes the best choice. It adopts the technology of variable bandwidth using PLL software in the RF PLL module, which can obtain high speed frequency hopping in wide bandwidth and keep the lock in a smaller bandwidth, in order to gain the lowest phase noise and highest spurious rejection. With the increasing of the components assembled in the two independent PLL circuit, the power consumption and size will increasing as well. So it adopts four layers PCB to solve problem caused by the peripheral devices and placements increased in the two single PLL circuit, and optimal allocate the power consumption of the next stage circuit to meet the requirements for system.In order to realize the performance of the miniature low power high-speed hopping frequency source, it analyses and calculates key technical parameters: phase noise, spurious rejection and frequency hopping speed. It also analyses and sums up all kinds of difficult problems in the production and debugging, finds out the reasons and proposes the method and results of problem solving. The test results and photographs of the frequency source are finally shown in the article. It analyses the test results and develops an improved proposal and work plan according to the difference between the theoretical parameters and the actual test datas.