题型:填空题 理想低通滤波器,适用无()干扰,而()干扰较严重的地区.它的频率响应为H(f)=1.当┃f┃《┃fc┃时;H(f)=0.当┃f┃》┃fc┃时,对应的脉冲响应为:h(t)=(1/πt)sin(2πfct) 查看答案
题型:选择题 The actor________us greatly with his wonderful performance and excellent English. [ ]A.movedB.interestedC.impressed D.touched 查看答案