I plan to use FCA3120 counter to measure ~10GHz signal against a very good external reference (AD@1s ~10^-13) What is the instrument measurement floor with an external reference? An AD chart from 1ms to 100ks would be ideal to see. I found the instrument's datasheet shows a stability chart with various quartz oscillators (page 7) but I do not think this is the floor limit. Thank you. Anatoliy.