【正文】 n cannot change once established. Using the LabVIEW virtual instrument is made of the virtual technology, puter technology, bus technology, and software technology closely together. It use puter powerful digital processing ability realize the instrument most of the functions, breaking the traditional instruments of the framework, formed a new instrument mode. To this end, this paper presents a low frequency analog signal display analyzer design. Low frequency analog signal analyzer design is mainly divided into two parts of the upper machine and lower machine. Lower machine mainly used C8051F340 MCU of signal sampling and signal will be sent to PC through USB interface. Upper machine mainly by the PC to the GUI interface for waveform display store spectrum analysis. On the software, I/O port, timer, ADC, initialized clock, and then to generate the waveform sampling and via USB to a PC Then the waveform sampling and via USB to a PC. In the PC using the LabVIEW virtual instrument design an oscilloscope waveform display and frequency analysis. On the hardware, we will produce the first on the analog signal sent to the A/D converter, so that it is converted to digital signals . PC to the GUI interface displayed waveform and frequency spectrum analysis. After debugging, finally validate this design realized the function of the above mentioned, innovative and use value. According to the analyze of the application, it es into being the design scheme of the system in the beginning, then gives the detail description from hardware and software both sides, finally gets the verification of the system function through the system debugging and analyze. KEY WORDS： C8051F340， LabVIEW, spectral, analysis, personal puter, 西安工程大學(xué)本科畢業(yè)設(shè)計 (論文 ) USB 西安工程大學(xué)本科畢業(yè)設(shè)計 (論文 ) 目 錄 前 言 ............................................................... 1 第 1 章 系統(tǒng)原理與方案 ............................................... 3 基本原理 .................................................... 3 采樣的基本原理 ......................................... 3 API 實現(xiàn) USB 通信原理 ................................... 4 LabVIEW 軟件設(shè)計基本原理 ............................... 5 系統(tǒng)方案設(shè)計 ................................................ 6 系統(tǒng)功能 ............................................... 6 系統(tǒng)方案 ............................................... 7 系統(tǒng)結(jié)構(gòu)框架 ...................................... 7 器件選擇 ......................................... 7 軟件環(huán)境 ........................................ 11 測試方案 ........................................ 11 論文章節(jié)安排 ............................................... 12 第 2 章 硬件設(shè)計 .................................................... 13 硬件功能描述 ............................................... 13 硬件總體設(shè)計 ............................................... 13 硬件詳細設(shè)計 ............................................... 14 單片機最小系統(tǒng) ........................................ 14 供電電路 ......................................... 15 復(fù)位電路 ......................................... 16 JTAG 電路 ........................................ 17 USB 通信與供電電路 .................................... 17 USB 通信電路 ..................................... 17 電源電路 ......................................... 18 系統(tǒng)硬件原理圖設(shè)計 ......................................... 18 西安工程大學(xué)本科畢業(yè)設(shè)計 (論文 ) 系統(tǒng)整體 PCB 圖設(shè)計 ......................................... 19 第 3 章 軟件設(shè)計 .................................................... 20 軟件功能概述 ................................................ 20 下位機 ................................................ 20 上位機 ................................................ 20 軟件總體設(shè)計 ............................................... 20 軟件詳細設(shè)計 ................................................ 22 下位機程序設(shè)計 ........................................ 22 初始化 .......................................... 23 數(shù)據(jù)采集并通過 USB 發(fā)送 ........................... 24 上位機程序設(shè)計 ........................................ 25 前面板 ........................................... 25 后面板 ........................................... 26 程序代碼 ................................................... 31 第 4 章 系統(tǒng)調(diào)試 .................................................... 32 調(diào)試目的 .................................................... 32 驗證 USB 通信 .......................................... 32 驗證被測信號功能 ...................................... 32 驗證 LabVIEW 界面功能 .................................. 32 整體調(diào)試 .............................................. 32 調(diào)試方案 .................................................... 33 驗證 USB 通信成功 ...................................... 33 硬件方面檢測 .......................................... 33 檢測被測信號 .......................................... 34 整體調(diào)試 .............................................. 34 調(diào)試結(jié)果 ................................................... 34 調(diào)試過程中遇到的問題及解決方案 ............................. 36 結(jié)論與分析 .................................................. 36 第 5 章 結(jié)論與展望 .................................................. 37 西安工程大學(xué)本科畢業(yè)設(shè)計 (論文 ) 結(jié)論 ........................................................ 37 展望 ........................................................ 38 參考文獻 ........................................................... 39 致 謝 .............................................. 錯誤 !未定義書簽。硬件上 ， 先將產(chǎn)生的模擬信號發(fā)送到 A/D轉(zhuǎn)換器上 ,使其轉(zhuǎn)換為數(shù)字信號 ,然后發(fā)送到 PC機上。為此，本文提出了低頻模擬信號顯示分析器。利用 LabVIEW 做成的虛擬儀器是將虛擬技術(shù)，計算機技術(shù)，總線技術(shù)，和軟件技術(shù)緊密結(jié)合在一起，利用計算機強的數(shù)字處理能力實現(xiàn)了儀器的大部分功能，打破了傳統(tǒng)儀器的框架，形成了一種新的儀器模式。軟件上， 下位機主要是對 波形進行采樣并通過 USB發(fā)給 PC機， 上位機上 利用 LabVIEW虛擬儀器設(shè)計一個示波器進行波形顯示和頻率分析。 經(jīng)過對 本設(shè)計的功能進行仔細分析，在論文開始得出了系統(tǒng)的總體設(shè)計方案，接著從硬件、軟件兩部分對系統(tǒng)的設(shè)計方案進行了詳細描述，最后又通過系統(tǒng)的調(diào)試和分析驗證了系統(tǒng)功能特性。與傳統(tǒng)的儀器相比其特點主要有 ： 具有更好的測量精度和可重復(fù)性 ； 測量速度快 ； 系統(tǒng)組建時間短 ； 由用戶定義儀器功能。信號波形顯示分析器是在科學(xué)研究和工程