第2章數(shù)據(jù)通信基礎(chǔ)

1、數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)1數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)2數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)3主機(jī)主機(jī)CCPCCPLANPrinterPrinterTerminal主機(jī)主機(jī)LAN數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)4數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)5數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)6 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)7 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)8數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)9數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)10數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)11數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)12數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)13s s( (a a) )s s( (t t) )l li im

2、ma at t 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)14)2sin()(ftAtst ts s( (t t) )，T T) )s s( (t t數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)15數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)16數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)17)5(2sin(51)3(2sin(31)2sin()(111tftftfts數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)18數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)19數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)20 TnTnTnnndtnfttgTbdtnfttgTadttgTccTfnftbnftactg0001)2cos()(2)2sin()(2)(21)2cos()2si

3、n(21)( 是是直直流流分分量量。是是基基波波頻頻率率，其其中中：數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)21數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)22數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)23數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)24基帶傳輸和頻帶傳輸基帶傳輸和頻帶傳輸 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)25數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)26數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)27數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)28(Differential Manchester Encoding)(Manchester Encoding)數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)29數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)30數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)

4、通信基礎(chǔ)31后的幅值。每個樣值的二進(jìn)制碼組稱為后的幅值。每個樣值的二進(jìn)制碼組稱為碼字碼字，其位數(shù)稱為其位數(shù)稱為字長字長。字長字長= =loglog2 2n n數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)32 2 4 6 810121416D7=1.31D6=9.29D5=15.215D4=10.811D3=5.66D2=2.83D1=2.7312Bt數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)33數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)345101501 0 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1樣本間隔時間被發(fā)送的位串?dāng)?shù)字化線連續(xù)的樣本總是相差1信號變化太快，以至編碼不能表示信號的變化數(shù)據(jù)通信與

5、計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)35數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)36 001)ft2cos(A)t(S當(dāng)當(dāng)數(shù)數(shù)字字信信號號為為當(dāng)當(dāng)數(shù)數(shù)字字信信號號為為 二元調(diào)幅二元調(diào)幅脈沖編碼脈沖編碼數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)37 0)tf2cos(A1)tf2cos(A)t (S21當(dāng)當(dāng)數(shù)數(shù)字字信信號號為為當(dāng)當(dāng)數(shù)數(shù)字字信信號號為為 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)38數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)39 0)ft2cos(A1)ft2cos(A)t(S當(dāng)當(dāng)數(shù)數(shù)字字信信號號為為當(dāng)當(dāng)數(shù)數(shù)字字信信號號為為 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)40數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)41三種類型的調(diào)制三種類型的調(diào)制數(shù)據(jù)通信

6、與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)42數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)43數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)44數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)45數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)46數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)47數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)48數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)49數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)50源系統(tǒng)傳輸系統(tǒng)目的系統(tǒng)傳輸系統(tǒng)源點(diǎn)終點(diǎn)發(fā)送器接收器輸入信息輸出信息輸入數(shù)據(jù)輸出數(shù)據(jù)發(fā)送的信號接收的信號數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)51數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)52數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)53數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)54數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)55數(shù)

7、據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)56數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)57數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)58數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)59數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)60數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)61數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)62同步字符數(shù)據(jù)1數(shù)據(jù)2數(shù)據(jù)n校驗字符CRC1校驗字符CRC2同步字符一幀下一幀數(shù)據(jù)場同步字符數(shù)據(jù)1數(shù)據(jù)2數(shù)據(jù)n校驗字符CRC1校驗字符CRC2同步字符一幀下一幀同步字符數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)63 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)64頻率頻率時間時間頻率頻率 1頻率頻率 2頻率頻率 3頻率頻率 4頻率頻率 5數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)6

8、5 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)66 1Channel 330031001Channel 21Channel 16064687260646872Channel 1Channel 3Channel 2頻率(KHz)(c)頻率(KHz)(b)頻率(Hz)(a)300 3400數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)67數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)68 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)69 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)70數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)71124.n13.n.1234.n時間片1時間片2時間片n125.m41257.m.1234.m時間片1時間片2時間片n數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)

9、據(jù)通信基礎(chǔ)72信道 24信道 1信道2信道3信道401193比特幀(125微秒）幀開始位7位數(shù)據(jù)位校驗位數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)73數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)74數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)75 共享光纖光柵光柵功率波長共享光纖的波譜功率波長光纖1的波譜功率波長光纖2的波譜光纖1光纖2光纖3光纖4功率波長光纖3的波譜功率波長光纖4的波譜數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)76數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)77 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)78 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)79數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)80 011miiiTSmTSmimiimiiimSmSSm11

10、2211)1(111SS數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)81數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)82數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)83數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)84數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)85數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)86(A(BCD數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)87數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)88數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)89數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)90數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)91數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)92數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)93 由于分組長度較短，在傳輸出錯時，檢錯容易并且重由于分組長度較短，在傳輸出錯時，檢錯容易并且重發(fā)

11、花費(fèi)的時間較少；發(fā)花費(fèi)的時間較少； 限定分組最大數(shù)據(jù)長度，有利于提高存儲轉(zhuǎn)發(fā)結(jié)點(diǎn)的限定分組最大數(shù)據(jù)長度，有利于提高存儲轉(zhuǎn)發(fā)結(jié)點(diǎn)的存儲空間利用率與傳輸效率；存儲空間利用率與傳輸效率； 公用數(shù)據(jù)網(wǎng)采用的是分組交換技術(shù)。公用數(shù)據(jù)網(wǎng)采用的是分組交換技術(shù)。報文分組：報文分組：報文：報文：報文號目的地址源地址校驗報文號目的地址源地址報文分組數(shù)據(jù)校驗報文分組號數(shù)據(jù)數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)94數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)95數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)96數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)97數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)98P1P3P4報文報文報文 報文P2P1P3P4P2P1P3P4P2P

12、1P3P4P2P1P3P4P2P1P3P4P2t 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)99數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)100數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)101數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)102數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)103數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)104數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)105數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)106數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)107數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)108 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)109 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)110數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)111數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)112數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)113數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)114數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)115 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)116 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)117 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)118垂直奇偶校驗（垂直奇偶校驗（VRCVRC） 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)119 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)120 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)121 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)122 數(shù)據(jù)通信與計算機(jī)網(wǎng)絡(luò)數(shù)據(jù)通信基礎(chǔ)