本文選題：微弱信號檢測 + 信號調理��； 參考：《南京信息工程大學》2017年碩士論文

【摘要】：微弱信號檢測技術快速發(fā)展,尤其在氣象傳感器方面得到了廣泛應用。在需要微弱信號檢測的領域中,各種微弱的物理量信號都需要先轉成電信號再進行放大處理。因此,對微弱直流信號檢測的研究具有重要的應用價值和理論意義。本文針對微弱直流電壓信號測量過程中易受噪聲干擾、測量精度不高、抗干擾能力差的問題,分析了微弱直流電壓檢測系統(tǒng)噪聲干擾,提出了抑制噪聲干擾的方法和措施,以MSP430F149為核心,設計了微弱直流電壓信號采集與測量系統(tǒng),實現(xiàn)了對10uv～45uv直流電壓測量。具體研究和設計內容如下:采用高精度放大器,低通濾波和陷波技術,設計了信號調理電路,降低了內部噪聲與外部干擾對微弱信號測量的影響。采用線性穩(wěn)壓芯片進行電源設計,減少了電源噪聲對測量精度的影響,降低了功耗。采用隔離技術,隔離了前端對模數(shù)轉換采集電路的影響。同時,設計了相關的信號顯示和存儲電路,實現(xiàn)了微弱直流電壓信號的采集與測量。在IAR開發(fā)環(huán)境中,采用模塊化思想,設計了系統(tǒng)下位機軟件。主要包括主程序、A/D轉換、顯示程序、數(shù)據(jù)存儲及通信程序等,通過主程序調用各模塊的子函數(shù)完成系統(tǒng)功能,各個模塊間采用全局變量和函數(shù)的參數(shù)進行信息傳遞。上位機監(jiān)控軟件采用Delphi和Access數(shù)據(jù)庫開發(fā)。主要由數(shù)據(jù)采集、數(shù)據(jù)查詢與顯示、下位機校準等功能模塊構成。下位機采集數(shù)據(jù)通過串口將數(shù)據(jù)發(fā)送到上位機保存、顯示和處理。系統(tǒng)通過校準電路、軟件數(shù)字濾波和基于最小二乘法的曲線擬合對測量結果進行補償。校準電路中,將壓值偏差寫入存儲器,系統(tǒng)開機后讀取存儲器校準值以修正輸出。采用防脈沖干擾平均濾波法對隨機噪聲進行濾波處理,兼顧了中值濾波和算術平均值濾波的優(yōu)點。基于最小二乘法擬合誤差曲線,對測試電壓值進行補償輸出。通過系統(tǒng)仿真和硬件測試,表明系統(tǒng)可以實現(xiàn)對10uv～45uv直流電壓測量,并能將采集的數(shù)據(jù)進行自動存儲和顯示。在連接PC機的情況下,能通過串口實時將電壓數(shù)據(jù)發(fā)送至上位機保存、顯示和處理。
[Abstract]:Weak signal detection technology has developed rapidly, especially in meteorological sensors.In the field of weak signal detection, all kinds of weak physical signals need to be transformed into electrical signals and then amplified.Therefore, the research of weak DC signal detection has important application value and theoretical significance.In this paper, the noise interference of weak DC voltage detection system is analyzed, and the methods and measures to suppress the noise interference are put forward in order to solve the problem that the weak DC voltage signal is easy to be disturbed by noise, the measurement accuracy is not high and the anti-interference ability is poor.Taking MSP430F149 as the core, the acquisition and measurement system of weak DC voltage signal is designed, and the DC voltage measurement of 10uv~45uv is realized.The specific research and design contents are as follows: using high precision amplifier, low pass filter and notch technology, the signal conditioning circuit is designed to reduce the influence of internal noise and external interference on weak signal measurement.The linear voltage stabilizer chip is used to design the power supply, which reduces the influence of the power noise on the measurement accuracy and reduces the power consumption.Isolation technology is used to isolate the effect of front end on A-D conversion acquisition circuit.At the same time, the related signal display and storage circuit are designed to realize the acquisition and measurement of weak DC voltage signal.In the development environment of IAR, the software of the lower computer is designed with the idea of modularization.It mainly includes the main program called A / D conversion, display program, data storage and communication program, etc. The system functions are completed by calling the sub-functions of each module by the main program, and the global variables and the parameters of the function are used to transfer information among the modules.The host computer monitoring software is developed by Delphi and Access database.Mainly composed of data acquisition, data query and display, lower computer calibration and other functional modules.The data collected by the lower computer is sent to the upper computer through serial port to save, display and process.The system compensates the measurement result by calibrating circuit, software digital filter and curve fitting based on least square method.In the calibration circuit, the bias of the voltage value is written to the memory, and the system reads the calibration value of the memory to correct the output after the system is turned on.The average filtering method against impulse interference is used to filter random noise, which takes into account the advantages of median filter and arithmetic average filter.Based on the least square fitting error curve, the test voltage value is compensated and outputted.The system simulation and hardware test show that the system can measure the DC voltage of 10uv~45uv and can automatically store and display the collected data.In the case of connecting PC, the voltage data can be sent to the host computer to save, display and process through serial port in real time.
【學位授予單位】：南京信息工程大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TN911.23

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