设信道带宽为3000Hz，信噪比为30db，则信道可达到的最大数据速率约为(23)bit/s。

(63)

(61)

(62)

(66)is　a　channel'　s　capacity　which　directly　reflects　the　data　transfer　rate　of　the　channel.(67)functions　in　a　NetWare　network　which　is　used　to　define　addressing　schemes.(68)is　a　network　layer　device　that　suports　multiple　LAN　interfaces　and　segments　LANs　into　smaller　collision　and　broadcast　domains.(69)．is　the　popular　LAN　develped　under　the　direction　of　the　IEEE　802.3.(70)is　a　device　which　enables　digital　microcomputers　to　communicate　across　analog　telephone　lines.

(60)

Functional　testing　tests　whether　the　output　is　the　expected(75)with　the　valid　input.

The　Programming　languages　are　designed　to(74)the　communication　between　human　and　computers.

Without　systems　software,　application　software　in　a　computer　is(73)

Windows　XP　is　Microsoft's　most　advanced　desktop(72)system.

A　computer　virus　is　a　computer　program　that　is　created　to　make　and　spread(71)of　itself.