John Kenney, Principal Hardware Design Engineer, Juniper Networks
Peter Pupalaikis, Vice President and Principal Technologist, LeCroy

This paper discusses the common problem of making setup and hold measurements in memory systems where the desired probing point is inaccessible. Timing measurement problems of this type are problematic not only in skew due to incorrect probing locations, but also due to waveform distortions due to reflections created by various termination schemes. The paper considers various problems specifically in termination methods utilized in memory systems and offers some solutions and methods for mitigating measurement problems. A real-life example in a QDR memory system is used.