common mode termination what is it
Hello,
you shouldn't overvalue such "principle" schematics as from the said National document. I would rather regard datasheet specifications as solid facts, although some properties are still left open. From the datasheets, it's clear, that common mode voltage is within narrow bounds arround 1.2V. Thus your conclusions regarding common mode impedance must be basically correct.
Differential receiver impedance is out of doubt, but differential transmitter impedance seems to be almost unspecified. Surely it isn't forbidden to have it at 100 Ohms, but it may be also above or below to my opinion. I noticed, that all manufacturer apparently are avoiding a specification with their LVDS related products. To my opinion, it won't get you anywhere trying to interpret non-information.
It may be interesting to measure empirical impedance properties of LVDS interfaces, but I didn't feel yet a need to.
Regards,
Frank