Mop-Up Equalization of Certian AM-PM Distortion Effects in FDM-FM Transmission Systems

In frequency division multiplexing (FDM)-FM transmission systems, unequalized parabolic delay preceding a component with AM-PM conversion can be an important source of intermodulation distortion. This correspondence describes some manifestations of these distortion effects and indicates how the distortion can be reduced with cubic IF amplitude equalizers applied on a mop-up basis.