【正文】 人將系統(tǒng)清除為止 ； 如果定時時間已到，無人搶答，本次搶答無效，系統(tǒng)報警并禁止搶答 。 If the fixed time has already arrived, no man robs, this time robbing an answer invalid, the system warns and forbid to rob an answer. Pass by wiring, welding, and adjusting the digital rob an answer machine is pleted after the design of the electric circ Keywords rob an answer machine。 warning electric circuit 哈爾濱理工大學遠東學院學士學位論文 IV 目錄 摘要 .......................................................................................................................I Abstract ............................................................................................................... II 第 1 章 緒論 ........................................................................................................ 1 第 2 章 總體方案設(shè)計 ........................................................................................ 2 設(shè)計內(nèi)容與要求 ....................................................................................... 2 數(shù)字搶答器總體方框圖 ........................................................................... 2 本章小結(jié) ................................................................................................... 2 第 3 章 單元電路的設(shè)計及參數(shù)計算 ................................................................ 4 單元電路的設(shè)計 ....................................................................................... 4 搶答器電路 ........................................................................................ 4 定時電路 ............................................................................................ 4 報警電路 ............................................................................................ 6 時序控制電路 .................................................................................... 7 參數(shù)計算 ................................................................................................... 8 二極管閃爍及間隔時間計算 ............................................................ 8 報警發(fā)生時間 的計算 ........................................................................ 9 總體電路圖 ............................................................................................... 9 本章小結(jié) ................................................................................................... 9 第 4 章 元器件的功能和作用 .......................................................................... 10 555 定時器 .............................................................................................. 10 555 定時器內(nèi)部結(jié)構(gòu) ........................................................................ 10 定 時 器 原 理 .................................................................................................................... 10 同步十進制可逆計數(shù)器 74LS192 ......................................................... 11 8 線 3 線 優(yōu)先編碼器 74LS148 ............................................................. 12 譯碼器 74LS48 ....................................................................................... 13 數(shù)碼顯示譯碼器 ..................................................................................... 15 單 穩(wěn)態(tài)觸發(fā)器 74121 .............................................................................. 16 單穩(wěn)態(tài)觸發(fā)器 74121 的工作原理 .................................................. 16 管 腳 圖 及 功 能 表 .................................................................................................................... 16 本章小結(jié) ................................................................................................. 17 第 5 章 印制電路板的設(shè)計 .............................................................................. 18 Protel 2021 概述 ...................................................................................... 18 哈爾濱理工大學遠東學院學士學位論文 V 印制電路板的設(shè)計 ................................................................................. 19 印制電路板 簡介 .............................................................................. 19 原理圖的設(shè)計規(guī)則 .......................................................................... 19 印制電路板設(shè)計的基本原則 .......................................................... 20 PCB 板圖的設(shè)計 ..................................................................................... 21 本章小結(jié) ................................................................................................. 21 第 6 章 系統(tǒng) 的組裝與 調(diào)試 .............................................................................. 22 元器件的焊接 ......................................................................................... 22 手工錫焊基本操作 .......................................................................... 22 手工錫焊技術(shù)要點 .......................................................................... 23 系統(tǒng)的組裝與調(diào)試及測試方法 ............................................................. 23 組裝與調(diào)試過程中遇到的問題及解決方法 ......................................... 24 本章小結(jié) ................................................................................................. 24 結(jié)論 .................................................................................................................... 25 致謝 .................................................................................................................... 26 參考文獻 ............................................................................................................ 27 附錄 A ................................................................................................................ 28 附錄 B ................................................................................................................ 30 附錄 C ................................................................................................................ 31 附錄 D ................................................................................................................ 32 附錄 E.........................................