题目内容:
回答题:Inthefollowingessay,eachblankhasfourchoices.Choosethebestanswerandwritedownontheanswersheet. Spreadspectrumsimplymeansthatdataissentinsmallpiecesoveranumberofthe__(71)__frequenciesavailableforuseatanytimeinthespecifiedrange.Devicesusing__(72)__spreadspectrum(DSSS)communicateby__(73)__eachbyteofdataintoseveralpartsandsendingthemconcurrentlyondifferent__(74)__.DSSSusesalotoftheavailable__(75)__,about22megahertz(MHz).(71) A.continuous
B.high
C.low
D.discrete
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答案解析: