How do I calculate an accumulative rms of a vector and stop when an increase/decrease occurs?

I have a set of thousands of curves that all have the same general trend. They oscillate around an rms of about zero, and then they increase at a certain point. I want to find this point for each graph. I should point out that this point can be 2*rms for one graph, while it can be 10*rms for another. How do we do this?

Answer 1

[Jan]

At first find a reliable mathematical definition of what you are looking for. If teh criterion differs from signal to signal, a magic tool would be required.

[Natalie]

In regards to "magic" being required - not a bad idea. But seriously, the criterion: Once the accumulative rms (of y(0) till y(stop)) increases, we stop and set the point to y(stop).