differentiating amplifier英 [ˌdɪfəˈrenʃieɪtɪŋ ˈæmplɪfaɪə(r)]美 [ˌdɪfəˈrenʃieɪtɪŋ ˈæmplɪfaɪər]微分放大器;差频放大器计算机