Agilent Technologies Inc. has introduced a probe kit for making differential time-domain reflectometry (TDR) and time-domain transition (TDT) measurements. The N1021B is an 18-GHz kit that connects printed circuit boards to the 54754A differential TDR/TDT module in the 86100C Infiniium DCA-J wideband oscilloscope mainframe. The optional 86100C-202 impedance and S-parameter software characterizes differential impedances in the time and frequency domains. The probe’s thumbwheel enables one-hand pitch adjustments. Hardened tips ensure many touchdowns, and the chamfered design makes good contact, even on small pads or traces.