signal attenuation短语¹³¹⁶²⁰⁺³ 基本例句 信号衰减 In the second chapter, the feature of noise, impedance and signal attenuation of power line communication channel are analyzed. The conclusion of time vibration and random city is drawn. 第二章分析了电力线载波通信信道的噪声、阻抗和衰减特性，得出这些特性均具有时变性和随机性的结论。 cnki