The purpose of equalization is to compensate for the affect of a transmission line, specifically in a loss of signal strength. There are two areas where this loss can be compensated; at the transmit side using pre-emphasis as shown in the image on the top left of this slide, where voltage levels are emphasized by the same loss expected from the transmission line, and at the receiver edge where equalization is used to clean the distortion of the signal eye. The specific settings available on the Cyclone® IV GX are shown in the table.