Differential signal measurement in practiceTo measure a differential signal, we have two options, one is using a differential probe and second is using a two channels oscilloscope. A differential probe is expensive but handles a better accuracy. Using two/four channels oscilloscope is the cheapest method which handles acceptable results.Just you need to connect oscilloscope’s Channel-1 to one of the differential lines/wires and Channel-2 to another one. Then go to the math function and enable CH1-CH2 which means a difference. Then adjust the oscilloscope to observe the signal. You use the run/stop or a single shot button to freeze the signal on the screen and examine it.I have examined the ADSL2+ signal on the telephone line using the above-mentioned differential measurement method.Reference: http://bit.ly/2Z7sDTt