加性噪声一般指热噪声、散弹噪声等，它们与信号的关系是相加，不管有没有信号，噪声都存在。而乘性噪声一般由信道不理想引起，它们与信号的关系是相乘，信号在它在，信号不在他也就不在。-The additive noise generally refers to the thermal noise, shot noise, which is added with the signal of the relationship, or no signal, noise are present. While the multiplicative noise in general by the channel caused by non ideal, they are multiplied by the signal, signal in it, the signal is not in him is not in.