Need help understanding how to make an oscilloscope measurement. I have a DC signal that in normal state is held at logic '0'. During ESD/EMI I see a series of transient pulses swinging from about -3 to 15VDC. I am currently probing with active probe between the signal and reference ground. Probe is 1GHz BW active type. Leads are ~3" (both signal and gnd). The problem is a logic '1' will cause a power down or low power event. How do I perform this measurement reliably and confirm that the EMI that is being generated near the circuit is also really causing this logic '0' signalling to trigger a power down event through the series of spikes? Logic '1' is defined as 3.3VDC, minimum time is not defined, signal is labeled as asynchronous, I assume there is some associated response time, but there are no published specifications. Would measuring the ground (null measurement) and the signal then doing a CH1 minus CH2 pseudo-differential provide a more accurate representation? True differential measurement with diff amp/probe between ref gnd and signal? Shorter leads? AC Couple? Some combination of everything? Thanks for the help!