【正文】 ultrasonic inspection is often pared to quickly, easily, and calculate a simple, easytoachieve realtime control. Common ultrasonic distance principle is the pulse method, using an ultrasonic pulse emitted to receive reflected pulse of and ultrasonic in air speed multiply distance. Implementation features process simple, but accuracy is not enough. Laser distance measurement you can take advantage of the phase, laser range precision phase is very high, but more plex to implement. Topic is on the ultrasonic pulse range finder, an improved borrowing laser phase difference ranging method, but not exactly the same, but the use of wires, are two measuring points. End of the emission ultrasonic, on the other end of the cable to receive, and then by phase two of the phase change monitoring to measure the distance between two points of relative motion. The measurement results are divided into two parts, part of the current phase difference valuesmonitoring current instantaneous phase difference, this is a less than or equal to the value of the 360 degrees。 the fourth part of the CPLD programmable features to implement, use phase difference measurement distance of algorithms for analysis。 CPLD 西南交通大學本科 畢業(yè)設計 (論文 ) 第 VI 頁 目 錄 摘 要 .................................................................................................................................I ABSTRACT............................................................................................................................... V 第 1 章 緒 論 ...................................................................................................................... 1 課題的研究背景 ...................................................................................................... 1 課題的國研究現(xiàn)狀內外 .......................................................................................... 1 論文的研究內容 ...................................................................................................... 2 論文的結構安排 ...................................................................................................... 2 本章小結 .................................................................................................................. 3 第 2 章 整體方案分析和設計 .............................................................................................. 4 功能分析 .................................................................................................................. 4 系統(tǒng)主要功能 ................................................................................................ 4 系統(tǒng)方案的分析 ............................................................................................ 4 系統(tǒng)總體設計 .......................................................................................................... 5 工作原理 .................................................................................................................. 5 軟件實現(xiàn)工作框圖 ......................................................................................... 6 整周期計數(shù)模塊流程圖 ................................................................................ 7 本章小結 .................................................................................................................. 7 第 3 章 硬件電路的設計 ...................................................................................................... 8 時鐘信號及超聲波信 號源產(chǎn)生電路 ...................................................................... 8 時鐘信號簡介 ................................................................................................ 8 時鐘信號及超聲波信號源產(chǎn)生電路 ............................................................. 8 超聲波發(fā)射模塊設計與實現(xiàn) .................................................................................. 9 超聲波概念簡介 ............................................................................................ 9 40KHz 超聲波發(fā)射電路 .............................................................................. 10 超聲波接收電路設計與實現(xiàn) ................................................................................ 10 兩路同頻信號數(shù)字鑒相電路 ................................................................................. 11 數(shù)字鑒相器簡介 .......................................................................................... 11 數(shù)字鑒相器選擇方案比較 .......................................................................... 12 波長數(shù)量累加模塊 ................................................................................................ 13 基本 RC 積分電路原理簡介 ...................................................................... 13 電壓比較電路 .............................................................................................. 14 波長數(shù)量累加模塊功能介紹及電路實現(xiàn) .................................................. 15 西南交通大學本科 畢業(yè)設計 (論文 ) 第 VII 頁 數(shù)碼管顯示電路 .......................................................................................... 16 CPLD 模塊 ................................................................................................... 17 本章小結 ................................................................................................................ 17 第 4 章 CPLD 可編程功能實現(xiàn) ........................................................................................... 18 CPLD 介紹及 EDA 設計流程 ............................................................................... 18 CPLD 簡介 ................................................................................................... 18 EDA 的設計流程 ......................................................................................... 18 系統(tǒng)頂層原理圖及整體功能介紹 ........................................................................ 21 系統(tǒng)頂層原理圖 .......................................................................................... 22 各模塊功能簡介 ............................................................................