【单选题】调频信号uFM= Usmcos(2p ´106t + 15sin2p ´103t),先混频后倍频扩展线性频偏,得到u²FM= U²smcos(2p ´106t - 60sin2p ´103t),则倍频数n和本振信号的频率wl为( )。
A.
n = 4, w l = 5 p ´ 10 6 rad /s
B.
n = 3, w l = 5p ´ 10 6 rad /s
C.
n = 4, w l = 2.5 p ´ 10 6 rad /s
D.
n = 3 , w l = 2.5 p ´ 10 6 rad /s