Digital design has become increasingly complex. In part, this stems from the proliferation of third-generation serial busses like USB and SATA. The rise of the PCI Express Base Specification 3.0 (PCIe Gen3) and fourth-generation Serial Attached SCSI (SAS) serial bus, with their respective 8 Gbps and 12 Gbps data rates, further complicates matters. As data rates increase, jitter budgets tighten. These days so much new functionality is being designed into electronic products that design margins are shrinking.