The Design Of The X-Band Linear Frequency Modulation Circuit System

With the rapid development and continuous improvement of science and technology, signal source for the requirement of each index are also gradually improved, including the frequency bandwidth, low phase noise, frequency stability etc. Through frequency synthesis method can generate a lot of high precision signal, at the same time, it also widely used in communications, equipment, instrumentation, and computer, and navigation equipment.This article elaborates how the application of phase locked loop technology in X band signal source design through the following parts. Firstly, analyze the theoretical phase-locked loop. Secondly, analyze the function, mathematical model and transfer function in each module of the phase locked loop. Thirdly, describe in detail for phase locked loop’s noise and how to optimize the noise. Fourthly, introduce three kinds of different design schemes of the X band linear, and also analyzed their advantages and disadvantages. Finally, using MATLAB software to simulate the whole loop phase noise, and tests the technical specification of the overall system by LAB VIEW, and the test result show that the output frequency satisfies basically to caper change from7.8GHz to8.8GHz.The design used of the HMC765for control chip, because of its high degree of integration can improve the stability of the whole system and reduce the chip area, it’s valuable to realize the design of the signal source.