In addition.some other noise types Multiplicative Noise Amplitude has changed during signal transmission process. S,(t)=a(t)s,(t) a(t)changes randomly (such as fading channel in mobile communication); Convolution Noise s.()=s(t)*B()(such as multi-path effect impulse response B(t)is a random process UESTC 3UESTC 何子述等 3 Multiplicative Noise ：Amplitude has changed during signal transmission process. changes randomly (such as fading channel in mobile communication); Convolution Noise ： 1 ( ) ( ) ( ) o s t t s t = 1 ( ) ( ) ( ) o s t s t t =  (such as multi-path effect ) impulse response ( )t is a random process ( )t In addition , some other noise types :