You put a digital SD-SDI color bar signal (SMPTE 259M) into your Tektronix VM700T, and measure the color bar signal (if you have the SD-SDI option for this scope). You then send the SD-SDI color bar signal into your Digital to Analog converter, and use the VM700T analog composite input to observe the analog color bar signal that has been coverted. The levels on the analog display should be the same as the SD-SDI display. You are looking for accuracy in conversion of luminance and chrominance levels. It is very difficult on a web forum like this to show you a picture of what you should be looking for - I do not know if you have used a waveform montior and vectorscope display before, and I do not know if you know what to look for.
Tektronix has training material on their website http://www.tek.com on how to read a waveform monitor, but it is always easier if someone in person shows you what to look for.