How to generate a randomized signal?

I am trying to generate something like this:

http://i.imgur.com/zEFpMcb.png

I want the baseline to be zero, but have randomized sinusoidal fluctuations (in terms of amplitude and frequency) at random locations with random width. In other words, I want the following parameters to be random:

excitation frequency, excitation amplitude, excitation duration (width), and excitation location

As stated before, I want the excitation to be sinusoidal. I generated the signal in the image above, but I defined the values of the parameters.

Can anyone help me with the code for this? I have some preliminary code, but its not much and I am stuck.

EDIT: Some additional information:

I want there to be 3000 excitations, and the duration to be quite long.