When refining the PEC curve, it is suggested/assumed to add curve 1 and curve 2. Why aren't we averaging curve 1 and curve 2? What would happen if this was done for a series of refining PEC curves?

In general:

1. If two curves were both created with PEC *off* then you want to average the PEC curves.

2. If one curve was created with PEC off and the other with PEC on then you want to add the PEC curves.

What PEMPro does is #2. The curve with PEC on is residual, or uncorrected periodic error. It needs to be added back into the first PEC curve (with PEC off) to make the original curve account for the measured discrepency.

-Ray