# Simplified analytical model of LIGO signal

What is a simplified analytical model of the LIGO signal? It looks like a chirped sinusoid, but somewhat asymmetric.

Wikipedia shows some pictures of these signals, but the signal model is generated using numerical relativity codes, which is unnecessarily complicated for my use case (which is to do some practice in signal processing on widely-available real data).

• The second half of the response looks like a damped sinusoid, as shown in this article: en.wikipedia.org/wiki/Damped_sine_wave. The first half of the signal looks like a brief exponential rise in a sine wave. If you use piecewise continuous functions, and splice them together at the maximum point, you should get something that is a reasonable approximation. – David White Dec 28 '18 at 3:03
• @DavidWhite: Not sure that's totally satisfying; it would be just as natural to fit it with a spline. I was hoping for a very simplified model starting from the black holes/neutron stars merging. – user14717 Dec 28 '18 at 4:20
• I've seen splines in action before. If you need any derivatives of your data, you may find that a spline fit goes vertical in spots. Computers don't like that, as dx goes to zero in that spot and they don't like to divide by zero. – David White Dec 28 '18 at 6:23