87.1 Digital Filter Specifications e. We discuss in this course only the magnitude approximation problem .. There are four basic types of ideal filters with magnitude responses as shown below (e) Hp(e) -oc0(c -Oc T HBP(e) 压s(e0) 丌-0c2-0c1 ocl (c2 7t 丌-0c2-oc1 oc1oc2π§7.1 Digital Filter Specifications • We discuss in this course only the magnitude approximation problem • There are four basic types of ideal filters with magnitude responses as shown below