Now that you mention it, I'm not sure why I thought why each piece was 2 ms.

Looking again it looks closer to 3 ms.

Luckily it does not matter for the calculation whether the pieces are 2 ms or 3 ms.

As long as they have the same duration.

It the signal is shifted up by 1 V, the squares change, and the resulting RMS value will be higher.

And yes, you can't just look at the peak and divide by

.

It depends on the shape of the signal what the RMS value is.

For a sine wave, the RMS is the amplitude divided by

, but for a square wave, it is simply its amplitude.