You didn't say how you saved it, but clearly you've not saved it with enough precision because there are several points with the same x-value.

How did you save it (and which version of the tools are you using to save it?)

Andrew.

How can I increase the resolution?

I'm using calculator button, evaluate the buffer and display result in table, from the table save as CSV.

Is this the right way?

Which version are you using (as I asked before)? I want to make sure I tell you the right way to control the precision, because this may vary depending on the version used.

Andrew.

IC6.1.5-64b.500.8

Actually there are only a couple of different approaches. If using IC615 ISR6 onwards (6.1.5.500.6 or later) or using any IC61 version prior to the release of IC615, or using wavescan in IC5141:

Select the columns you want to change the precision click on them - or shift-click to select a range of columns (and do Right Mouse->Format and increase the number of digits, or use View->Format)

If using IC5141 with AWD or using early versions of IC615 (where the new Qt table widget wasn't ready yet) do Expressions->Display Options (in the Results Display Window) and alter the number of significant digits.

Then save the CSV file. 

I see now you've stated you're using IC615 ISR8, so the topmost approach should work for you.

Andrew.