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【多选题】
下列关于PM与FM之间关系的说法,正确的是( )。
A.
将调制信号先微分，而后进行调频，即可得到调相波
B.
将调制信号先积分，而后进行调相，即可得到调频波
C.
即使预先不知道调制信号m(t)的形式，也能判断已调信号是调相信号还是调频信号
D.
调频和调相都属于角度调制
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