https://ww2.mathworks.cn/help/rf/examples/modeling-a-high-speed-backplane-part-3-4-port-s-parameters-to-differential-tdr-and-tdt.html
http://www.mohr-engineering.com/documents/CT100_OPMAN/CT100_TDR_Cable_Tester_Guide.php
http://www.mohr-engineering.com/tdr-cable-tester-CT100.php
http://www.mohr-engineering.com/TDR_for_Microwave_RF_and_Digital_Cables-A.php