Advances in Time Domain Reflectometry characterisation for high speed interconnects

With the push towards higher speed signalling, and the demand for more accurate characterisation of the high speed interconnect elements, the Time Domain Reflectometer is becoming a very useful tool for displaying impedance over time showing the place and nature of discontinuities that lead to characteristic impedance mismatches and signal integrity issues. Currently, the need to meet regulatory compliance requirements can be achieved only by performing signal integrity analysis and characterisations. This article reviews and summarizes the progress made in Time Domain Reflectometry measurements and explores the issues involved in making precision impedance measurements of high speed interconnects. Moreover, factors limiting the accuracy of Time Domain Reflectometry measurements, such as dynamic range, rise time degradation, spatial resolution, multiple reflections and their impact on developing high speed interconnects are discussed in detail.