1. A communications system, comprising: a transmitter configured to transmit a signal, the signal including a sequence of symbols, each symbol associated with a respective signal level; a receiver configured to: receive the signal including the sequence of symbols, generate an eye diagram of the signal by plotting the a representation of the signal on a unit interval graph having a horizontal axis indicating a unit interval of time and a vertical axis indicating a signal level, the eye diagram having one or more polygon shaped-eyes, determine a maximal convex subset within each eye by trimming the polygon shape of each eye along one or more cut lines to remove one or more concavities of the polygon shape, and determine a largest orthogonal rectangle that fits in the maximal convex subset of each eye, and select, for each eye, a sampling point at the signal level equal to the center of the largest orthogonal rectangle, the sampling point representing a symbol in the sequence of symbols; and a channel coupling the transmitter to the receiver.