Yes I’m sure, the tiny manual is pretty clear on what it outputs, it only lists SG-SDI and HD-SDI, and 720 is the minimum vertical resolution. I’ve tried a few composite signals, mainly old computer equipment (and a handheld device which supports it), and the unit definitely locks onto the signal properly. :/
So I’m pretty sure the converter is outputting SDI, but not in a format the Tek’s can deal with because it’s too new for them.