【摘要】：幅頻特性是一個(gè)網(wǎng)絡(luò)性能最直觀的反映,在現(xiàn)代電子測量中占據(jù)著重要的地位。本文著重分析了幅頻特性測試的工作原理,在對市場上幅頻特性測試儀的研究現(xiàn)狀進(jìn)行分析之后,確定了本系統(tǒng)的性能指標(biāo)和總體設(shè)計(jì)方案。根據(jù)設(shè)計(jì)方案要求,設(shè)計(jì)了一種幅頻特性自動(dòng)測試儀。此設(shè)計(jì)主要有掃頻信號發(fā)生電路、增益控制電路、信號處理單元、人機(jī)接口、GUI用戶界面等幾部分組成。其中掃頻信號發(fā)生電路采用低功耗DDS芯片AD9833,產(chǎn)生幅值可調(diào)的正弦波。具有頻率轉(zhuǎn)換時(shí)間快、頻率分辨率高、可編程控制等優(yōu)點(diǎn)。采用基于ARM Cortex-MO的32位微控制器lpclllx系列,實(shí)現(xiàn)被測信號的檢測。再加上增益控制電路,使這種幅頻特性自動(dòng)測試儀能適應(yīng)各種測試要求。配有LCD液晶顯示,調(diào)試方便,性能穩(wěn)定可靠,能夠在全頻段范圍內(nèi)自動(dòng)步進(jìn)測量,采用按鍵功能,可預(yù)置測量范圍及步進(jìn)頻率值,可以更加細(xì)致的觀察幅頻特性圖,經(jīng)測試,該幅頻測試儀能夠輸出有效值可調(diào)的正弦波、無明顯失真、全頻段幅度誤差在2%,輸出正弦波的頻率范圍為100HZ-5kHZ,交流信號的測量精度為0.07%、分辨率為0.01V,輸出阻抗小于10Ω,輸入阻抗大于100k。
[Abstract]:The amplitude-frequency characteristic is the most direct reflection of the network performance and plays an important role in modern electronic measurement. In this paper, the working principle of amplitude-frequency characteristic testing is analyzed. After analyzing the research status of amplitude-frequency characteristic tester in the market, the performance index and overall design scheme of the system are determined. According to the requirements of the design scheme, an automatic measuring instrument for amplitude and frequency characteristics is designed. This design consists of sweep signal generating circuit, gain control circuit, signal processing unit, man-machine interface, GUI user interface and so on. Low power DDS chip AD9833, is used to generate sinusoidal wave with adjustable amplitude. It has the advantages of fast frequency conversion time, high frequency resolution and programmable control. The 32-bit microcontroller lpclllx series based on ARM Cortex-MO is used to detect the measured signal. With the addition of gain control circuit, the automatic testing instrument of amplitude and frequency characteristics can meet various testing requirements. Equipped with LCD liquid crystal display, easy debugging, stable and reliable performance, automatic step measurement in full frequency range, key function, preset measurement range and step frequency value, more meticulous observation amplitude and frequency characteristic diagram, through testing, The amplitude-frequency tester can output sinusoidal wave with adjustable RMS without obvious distortion. The amplitude error of the whole frequency band is 2, the frequency range of output sinusoidal wave is 100HZ-5kHZ, the measuring accuracy of AC signal is 0.07 and the resolution is 0.01V. The output impedance is less than 10 惟 and the input impedance is more than 100k.
【學(xué)位授予單位】：南京理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：TN713;TP368.1

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