Plotting a Difference wave in Excel

I have plotted two approximately sinusoidal waves in one Excel graph.

Both waves are voltage, on the y-axis, against time the x-axis. Though both waves are not identical, being out of sync a little.


The first wave has quite a lot more readings which make it than the second wave.


If I want to produce another Excel graph depicting a wave of the difference in these two, how would I do that?


Thanks for any advice!

You will have to interpolate the values that you are missing. One suggestion would be to add a 2nd or 3rd degree polynomial fit to each line on the Excel graph and tick the box to show the equation of each of these fit lines.

Then when you have both equations you can make the values for whatever times you need.