The Software Design Of Microwave Cavity Temperature Sensor Detecting System Based On FPGA

Temperature detection has great significance and value to the industries like industrial manufacturing, aerospace aviation, etc. Especially under the condition of high temperature, a set of good temperature detection system is of great importance. A kind of microwave cavity temperature sensor which is made of Si CN ceramic material has the characteristics of high temperature resistance and quick response. In this thesis, a kind of microwave cavity temperature sensor detection system based on FPGA is used for detecting the temperature under high temperature condition. The temperature detecting range is from normal temperature to 300°C.This topic is based on the study of the temperature measuring process of microwave cavity sensor. Based on the analysis of the speed and accuracy of system temperature measuring process and in accordance with continuous measuring algorithm and data processing optimization, the detector which is used for signal generating, receiving, processing and displaying has been developed and the detection of the temperature sensor has been realized. This thesis carries out the research from the following aspects: Analyzing of the characteristic of microwave cavity temperature sensor which is made of Si CN ceramic material. Introducing the microwave cavity detection principle. Introducing the FPGA and related developing tool and programming language. Analyzing and studying the key frequency sweep signal generating chip HMC833LP6 GE and confirming the specific software designing proposal. Detailed introduction of the logic control part of FPGA will be given. The button module, HMC833 control module, SDRAM memory module, communication module and AD sampling and data processing module have been designed. Conducting simulation testing to each design module and analyzing the time sequential accuracy of each module. Time-consuming analysis to the whole detection system on software will be carried out. Then proceed with practical measurement. Through the measurement, the accuracy of the design of the system will be presented. At the end, a summary of the innovation points and insufficient points of this thesis will be given.To meet the project requirement of microwave cavity temperature sensor, the detection system based on FPGA has achieved the sweep frequency within the range of 5.4~5.5GHz. Determine the resonant frequency through the minimum value of feedback voltage by detection circulator so as to calculate and display the temperature. The single frequency phase noise of the signal source designed by this paper reaches-92.13 d Bc/Hz and the stray is suppress to-74.3d Bc. The locking accuracy reaches level of k Hz and the energy of the sweep frequency signal can reach 5d Bm. Through the test, it can conclude that the accuracy of the temperature detecting also within ±5°C. This system is of the characteristics of low cost, low power consumption, short development period, flexible design, etc. which has great practical value and wide application prospects.