Is your chart an XY or line chart?
If it is a XY chart it is easier.
You will need to set up a method on the spread sheet of identifying the peaks.
the method to do this depends on the noise in the data.
if the data between max and mins is always monotonically increasing or
decreasing you could use something like
=if(and(d3>d2,d3>d4),d3,na())
If there is a lot of up and down movement in your curves You will need to
put in a smoothing function
another way to do it is to select on the chart points which look like they
are maxes and record the x,y posion shown next to them.
record these positions on a new section of sheet plot it on the chart and
generate your trend line
A third way is to put in an XY plot of a line with the number of peaks you
expect to have with a max X equal to the max of the chart and a min X equal
to the min of the chart. Select each point on this line individually, and
drag it to be on a peak. once you have all of them moved. delete points you
didn't use and do a trendline on this data.
