Identify decaying or growing sinusoidal graph

I have a data set which either grows or decays over time.

The graphed data set looks like a sinusoidal graph with its amplitude either growing or decreasing over time.

What is the easiest way to identify if the overall trend is growing or decaying over time.

Thanks !

Answer 1

[Anton Semechko]

find the peaks, order them according to time and compare their magnitudes. see:

http://www.mathworks.com/matlabcentral/fileexchange/11755-peak-finding-and-measurement

or

http://www.mathworks.com/matlabcentral/fileexchange/25500-peakfinder