38 What happened in the 1970s?
A The US government called on its people to reduce their weight.
B Health experts persuaded restaurants to serve smaller portions.
C The United States produced more grain than needed.
D The American waistline started to expand.
第5题
k=1,2,3的三个Walsh函数作为CDMA系统的地址码,c1(t)=Wal(1,f),c2(t)=Wal(2,t),c3(t)=Wal(3,t)。分别求它们的自相关函数R11(τ),R22(τ),R33(τ)以及互相关函数R12(τ),R21(τ),R13(τ),R31(τ),R23(τ),R32(τ)(粗略画图形即可)。由所得结果讨论此码组是否能用做地址码。
第6题
A.互相关函数是偶函数。
B.互相关函数是奇函数。
C.任意两个统计独立的随机信号,其互相关函数等于0。
D.任意两个均值为0的统计独立随机信号,其互相关函数等于0。
为了保护您的账号安全,请在“上学吧”公众号进行验证,点击“官网服务”-“账号验证”后输入验证码“”完成验证,验证成功后方可继续查看答案!