I've just been watching Jim Williams' very excellent video on Measuring Switching Regulator Noise. At 1:58 Jim mentions a "50Ω back termination" in the probe setup that looks something like this (but not optional as it is in Linear app note AN-104 from which this diagram is taken):
It is a series 50 ohms, not parallel as at the scope connection, and as I understand it, its role is to absorb any reflections that might travel back from the scope.
My question is: "How is a 50Ω back termination typically accomplished in a scope probe line?"
I kind of suppose there's a through-termination that looks roughly like the common parallel ones, but instead of 50Ω between the center connection and ground, it is 50Ω between the center connection on either side. But I'll be darned if I can find such a thing on search.
Am I not using the right search term ("50 ohm series OR back termination oscilloscope"), or does such a thing not exist as I imagine and folks just solder a 50Ω resistor at the end of a piece of coax or something? :)