Design Of Ranging Baseband Signal Generator's Clock-frequency Correction And Control System

Ranging baseband signal is the core of the navigation and positioning system. This article which is under the subject"Development of Ranging Baseband Signal Generator"is going on in the background. In order to be able to provide accurate, reliable navigation signal and generate different modulation signals according to system requirement for navigation system, this article researched the clock source's generation and frequency correction algorithm and frequency synthesis techniques. I use MCU realize the control of the frequency source and other system module. It laid the foundation for achieving the whole baseband system.The main works of the article are:(1)detail the system overall framework and structure of ranging baseband signal, and give the function of each module.(2)research the clock frequency correction algorithm deeply, then design the clock frequency correction algorithm which is fit this system and realize it, use MCU realize the control and correction for frequency source, last give the result of the correction testing.(3)research the frequency synthesis techniques, generate the frequency signal by DDS and PLL hybrid-synthesis method, and use MCU control the relative peripheral circuits.(4)two important techniques used in the system: I2C and SPI which I studied and researched deeply in principle and technical details, and use MCU realize the controls and applications of I2C and SPI chips, so ensure the ranging baseband generator achieve greatly.Among them, the last three parts is the highlights of my work. Experimental results show that: the system frequency's stability meet the requirement of the design, synthesis frequency can output stably, realize the design program.