1)大信噪比情况A+m(t)>>n,(t) E()=[A+m(+24+mO)n(O)+n()+n1( NLA+m(t)]+2[A+m(t)]n(t) =[4+m()][1+ 2n(t)1 A+m(t) ≈[4+m()][1+ n1(t) A+m(t) A+m(t)+n(t) 有用12 1）大信噪比情况 A m(t) n (t) +  i ( ) [ ( )] 2[ ( )] ( ) ( ) ( ) 2 2 2 E t A m t A m t n t n t n t = + + + c + c + s [ ( )] 2[ ( )] ( ) 2 A m t A m t n t  + + + c 2 1 ] ( ) 2 ( ) [ ( )][1 A m t n t A m t c + = + + ] ( ) ( ) [ ( )][1 A m t n t A m t c +  + + A m(t) n (t) = + + c 有用