I'm assuming that the same rules apply as do in straight RF detection. A signal becomes a decent signal at 6db above noise and gets exponentially better every 6db above that. Something 20db above noise is rock solid reliable.
A signal 20db above the noise, you could put your eye out with it.
db is confusing, when you're talking voltage it's 20log(Vs/Vw) And in absolute terms engineers talk about the power over 1mW.
Myself I get miffed a bit because people have been conditioned to think in terms of trying to pull facts out of crappy data sets using poorly thought out statistics. However in a lot of engineering and physics fields the data is often really good. Often good enough that you can work off a single measurement.
