Lessons Learned in High Frequency Data Transmissions Design

Requirements of HEP experiments lead to highly integrated systems with many electrical, mechanical and thermal constraints. A complex performance optimisation is therefore required. High speed data transmission lines are designed, while simultaneously minimising radiation length. Methods to improve the signal integrity of point to point links and multi-drop configurations are described. FEA calculations are an essential guide to the optimisation which allow data rates of 640 Mbps for point to point links over a length of up to 1.4m, as well as 160 Mbps for multi-drop configuration. The designs were validated using laboratory measurements of S-parameters and direct BER tests.