简介:还 有一项活动有的学校只有毕业班学生参加,it is not .This is a daywhen all the seniors skip(注,而有的学校则是毕业班学生和十一年级学生一起参加
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简介:ThispaperdescribesafullchannelTVmodulatorforallTVsystems,whichhasbeendevelopedsuccessfully.ItemploysadvancedtechniquesuchasPLLfrequencysynthesizerwithmicrowaveintegratedcircuit,andwidebandmicrostripVCOanddigital-analogcombinedintegratedcircuits.Thekeytechniqueofthemodulatorissettledsuccessfully.AllthespecificationsofthemodulatoragreewithTechnicalStandardofChina,whicharetestedbytheauthorityofChina.