We clarify the role of signal loss measurements, aka Total Loss, in specifying and qualifying circuit board materials for high-speed electronic design. We then demonstrate the NIST Multiline measurement technique in particular by characterizing test lines fabricated in conventional PCB materials. The paper describes and demonstrates this technique, and shows how to accurately report signal propagation loss as a function of frequency, even when using TDR-based systems. The paper also reveals how impedance mismatch and differential delay variance contribute to the reported loss for various test methods in practice today. DesignCon 2011 Total Loss: How to Qualify Circuit Boards Don DeGroot, CCNi don.degroot@PCBmeasuements.com Peter Pupalaikis, LeCroy peter.pupalaikis@lecroy.com Brian Shumaker, DVT Solutions, LLC sales@gigaprobes.com Abstract We clarify the role of signal loss measurements, aka Total Loss, in specifying and qualifying circuit board materials for high-speed electronic design. We then demonstrate the NIST Multiline measurement technique in particular by characterizing test lines fabricated in conventional PCB materials. The paper describes and demonstrates this technique, and shows how to accurately report signal propagation loss as a function of frequency, even when using TDR-based systems. The paper also reveals how impedance mismatch and differential delay variance contribute to th……