数据通信技术.pdf

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32、JK?LMNO?PQ?RS/?TU?V?WXYZ?_6?9Oab?cde?fghiH?jkl?mnW?opqrstuvghwxynWz9|?I?8?9?9?MS?$?I?-?%-?,?x5678?=F?3AB?,.?fl?GHK?fl56789:;?,?W/?W01A?DEF?2_6COa3?Q?45?(6?78?c?se?ftugh?T?9V?:;!:?78O?WXT?O?78第四章?帧中继技术?4.2.2?Q?45?RS/&?&A./?&+,ATBCrRS/?JK?RS/&?C*?WD?EFRS/?-?&GHI?-/G?WXO?GHI?B?DH?I?H?D?JWXK?WXJWXK?KL?R

33、S/?x?RS/?r?KL?*?A?A?KL?数据通信技术数据通信技术数据通信技术数据通信技术?4.2.3?WX?W?M?Nt?OW78?78?,?PQWOJW/RST?NLU?Ntx?tu?M?V?Mb?O?W?$WX3?XtuW/?78YZYZO?WXC?tu?MT?N.?78?Q?S/?_?T?ab?Q?r?c78?T?dr?e?fg?h?P?WXRSTh?&i?j?d,V?FWXYZk0?WXRSTT?fiu?lm?Ntn?“N?WXl?8第四章?帧中继技术?!rs“N?o?T?Q?78,?R?dlm?pq?W4.2.4?gh6?WXrs?x781?,3t?O?WX?:u?vwx?78

34、?,?&?J?,?,?9?y?Q?i&?78?x?fiu4k?1yz?“N?WX4Q$?x?4,?i?4?i?&?|?G?v?y?O?4?NO?WX?4?!?l#?WXrs?tu?数据通信技术数据通信技术数据通信技术数据通信技术?4.2.5 PVC?-,Q?*WX?%?,?LM?WX*WX?-,LM,LM?*WXK?%?WX*WX?x?z?-?ojk?9f9?-?9?-?,LM?F?5?f?3?WXU?R?4.3?4.3.1?u?S?y?ghW?8?ghQ?%?WX?(?W9?W?W?W?9?GH?*?O?o?99m99“99*?9#GH?WfiflGH?r?9?GH?ghr?W?!gh?W?

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36、$?gh?OW?$?”4.3.2?OW?tu?y?W?4?j?4?%?h?9?9/?*?4?-?9!?-?9?%?.?/09?,?*W?4?J9GH?W?1?jk23?r?OW?7,9WX?,9WXf3,9o,?O,?3O?OW?W/?9S/?W/R?3?l?,?&?,?$?+?A?r?GH?,?4.3.3?WX?gh?r?gho?gh?EFRS/gh?-?9?$?EFRS/gh?$?-?$?T?RS/gh?$?-?ghjk?$?%?9?$?ghz?-?9?$?W/z?9?LMJ?LM?9?LM?*KL?./LM?&?=tP?o?y4?pI?!*V?z%&?g“?z?#gJK9?gJK9?Jl

37、UJK?P?z?k!k0?4?N78?$?$?%&?2?(4 第五章 数字数据网（DDN）?5.1 DDN?5.1.1 DDN?!?#$%?&#$?()?*+?(?,-.)?*+?#$*+/01?2?*+34?5?67?*8?9?:;?(*+34?A?*+?B?.?#$CDE?EFG?H?IJK?L?IJKM?N?O#$?P*+M?Q1?R?RS?TU?V?#WXY?Z?_?&a?bc?def?ghi?jkE?lm-no?pqrX?sturX2?vSM?O-w.IJKM*8?&ITU*8?xyzA?R?%?JK?2|M?-n-?.?*+?j?E?0?5.1.2 DDN?#$?xoa?f?0?1

38、.?(?)?S?ka?-f?2.?C?jk.?R9?,-?&?&jk?H?数据通信技术数据通信技术数据通信技术数据通信技术?3.?MODEMo?“?L?“?5?u3467?RSw?zfi7fl?&?“?7fl?:;?&?9?n?7fl?4.?”?a?L?E9?5.?!5.2 DDN?5.2.1 DDN?E?/0E?F?O?1.?#$%?w?(”?RS?E?(7fl?RS?“?LC?E?E_?-n?g?x?“?l?CL?(7fl,u?il?R?RS?&?7?&?9?2.DDN&?34?/0,?.?/0?(/0?/0?/0,?.?/0?/0n?m?/0?第五章 数字数据网（DDN）?/0?/0?.

39、?(?#$?pq?+?t?9?-n?R?9?,?CD?!?(/0?(/0?.?fi#$?(34?#?$!?%?9?&?!?jk9?*8?fi?(?m?34(?CD?!?(34!?/0?/0?!?/0?q?fi?34?%?数据通信技术数据通信技术数据通信技术数据通信技术?%?*8?&?#?$!?9?*8?fi?34?/0?#$?%?i?pq9?*8?-?g2?L?x?W?&?pq*8?/0?/0?!?xo/0R?a;?/0?,?m?/0?k?3.()?/01?/01?fi?E?-n?a?/0?V?ox?/0?/0g?-?R?Spq?4.?*+,-./0?S?q?M4?!?#$?%?-f34?(?

40、fi?&;!?(o?)*?q?+,E-.E/?$U0?q?o?)?1?o2-第五章 数字数据网（DDN）?5.2.2 DDN?3?E?4+,?5?6?7?,?.?m?.?E?8?.9?F?O?2?%?,?数据通信技术数据通信技术数据通信技术数据通信技术?1.1234?;a:E?Eg;?/0?x#$:1?;/0?8?L?ABC?DEL?fi;DEW(?/0?DE1?FGH?%?bc?s8?W(?/0?#$?%?Q1?+34?.IJ?l?&?#K?B?k?a?C?L?deE?fi?,LM?U?/0.?/0?M/0?NOf?/0Q1?P?Q?P?/0?RJoS?/0?Q!?DEW(?/0Q1EW(?

41、/0oO?/0?Q?C?fiTL?de?,a?US/0Q1?2.5234?;a:?/0?x#$?:?mEV?,?m?W?m?mEV?O;?E?(/0&?(/0?,?/0?&v?x/0?/0?3.67?m?N?XY?a:?,?m?.?#$?m?4.&8?#9:?!?/0?9?8?第五章 数字数据网（DDN）?/01?%?C?fiL?de?,?S?Q1?1?v?/0?x?/0?S:?9/0?/0Ov?/0?_?a!&!-f?!?5.3?DDN?(?,-?(7fl?&R/0?o“?F?O?%abcf?F?O?deRD?C?E!?*+?数据通信技术数据通信技术数据通信技术数据通信技术?&f?第五章 数

42、字数据网（DDN）?F?O?Od?jkE?-n?Hgh?iU?&f?RSf?jk?.x?g?2?i?gR?k?lE?mnop?_?A?K?jkjk?2?H?a?jk?qjr?t?.?2?Es?tuOv?!?&f?F?&?O?H?Ha?u?x?g?ghRS?mnotu&wxtu?a8?y?z?9?bc?(?CD?9?F?O?gh|?9?C?*?,-?9?C?*?+?,?-(.?*/?&(?&?9?-n?F?(?O?9?0?!?j?&?n?D?m?jk,?R!?1?|?1?2?E2?E?&?!?9?jk.?R?xP?a?jk.?jk,-?E?E?%?u?3?jk?“?,?&?EITU?jk.?R?

43、jk.?R?ITU?N?.P*+?_a?i?*8?pq?h?jkE?m0?+?2.(?4.?A?B?B?70i0?fi34pq?LC?0?R?N?B?q?L?6?a?Q?t?H?RCD?H?tu2sj?kK?L?vSW?R?2?“?7fl?p(?2,#K?jk?o?1?i?jk?-?a?def?k!?!?A?h.?n,LM?!?B?h+,?!?!)?LC*+?O-,H?.?h+,?#$?R?2*+?!uP“?x4?m?h+,?q?34?4?*+?)?7?.(?4?.?&;?F?RF?2s4?)?4D?6?)?*8?4?/0?5 第六章?计算机通信网?6.1?6.1.1?!?#?$?%&(?)*

44、+?,-./0?12?3456789:;?A?BCD;?$EFG?H?IJKL?MN?OP?QR?ST?6?$EUVWXYAZ?V?$_?3a?$_?b?$_?VWXY?cdef?gQ?hiejfk?lmno?MNpqrs?t?uvw?$E?VWXY?vdxef?7yz?l|a?MNpqrs?#?)$E?VWXYd?ef?l?k?l?c?A?a?$?b?$?(?$?=?A?$?6.1.2?LAN?$_?%?n?XYo?MN?:;?MN?$?$?$?,?数据通信技术数据通信技术数据通信技术数据通信技术?1?pq?$?3(?3?pq?upqrs?$Epq?“?Q?fifl?fi?3?6?$E?,”

45、?(rs?:;?($IJKL?$=?c0?K?pq?$=?W+?c?$E?fl?c?VW?c?k?fl?MNpq?s?NS?pq?(?s?v?6.1.3?$?v?V?AV?$V?3(?3?3?6?$?AV?$V?3?3$?3?3?67?$?pq?AV7V?$?$?$E?AV?$V?1?_?3?_?3?_?3_?!?$?第六章?计算机通信网?6.1.4?1.?IEEE802?#S9?fl?$?#?%?V?lV?t?OQR?ST?l?_$?)?=?#?%?V?#?%?$E)?#?$?)?S#$?%?/0?$?z?(?&?(?#?%?z?#(?/0_Q?&)*?$?z?/0+?H?)?$?=?/0?

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47、H?=D?B?v?$?=?P,?|?7te?|?MNFD?S?J?7?6H?=D?S?y1A6?YGp?n:?数据通信技术数据通信技术数据通信技术数据通信技术?$?=?flS?|V0?MN?fly1?&?(?MN?1M?1?KL?$E?S,?X?+?p(?MNUV?UVMN?X?+?(?7t:;?Yv?2?)?fl?$uv?fl?&?&?0?X?A?%?#?%?y?&?$?$?v?7?fl?6?QR?ST?*?&?!?+?&,?#$%&?()?R?*?(?A?.*(?&?G?6?*?&6?&?7?%?r?l?3?kS,?J?7?!?+%?n?”?I*(?/0?$?“1?S?$?fl?fl,C?

48、v?p?6?VQR?R?*ST?&?#&?-*./?-*()?-?&?,?&?,?,&,?-*.?()?0$%123?0123?04536789?:;数据通信技术数据通信技术数据通信技术数据通信技术?6.2?I?$?XY,x?IJ1?R?|?IJKL?XY?&?l?$?|?$E?($E?l?0?UV?KLIJ?4?$?v!?$eKMN$?$?peKMN$?$?peKMN$?|?R?$?$eKMN$?lxVe?x?f?$?6.2.1?uI?$?(?$?S(?$?%$E?O?(?$E?fl?(?:;flW?(?$?l”YV?(?$EOP?l$.?/!?(?t?QR?%ST?R?$?)?3=?$=?

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