Excel 2007 : getting the peaks of a jagged (non smooth) sine wave.

I am attempting to get the xy coordinates of the peaks of a very jagged sine wave i.e cant simply get local maxima as there are many false local maxima.

I have attempted this almost successfully by a)flattening the data and only sampling above a threshold thus elimating most false maxima. b) if y value> surrounding y values its a peak.

This does not narrow it down enough and i still end up with multiple peaks possibilties. I'd like a systematic approach where i enter any similar data and get peak coordinates?

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