The following example program is a simple demonstration of the function monte_carlo(), which was defined in the previous section. It produces animated output representing time-series data for simulated detector noise and for a simulated stochastic background having a constant frequency spectrum: for . The output from this program must be piped into xmgr. The parameters that were chosen for the example program shown below produce whitened time-series data for a stochastic background having for . For this particular example, the noise intrinsic to the detectors was set to zero. A sample ``snapshot'' of the animation is shown in Fig. .
By modifying the parameters listed at the top of the example program, one can also simulate an unwhitened stochastic background signal (Fig. ), and whitened and unwhitened data streams corresponding to the noise intrinsic to an initial LIGO detector (Figs. and ). Other combinations of signal, noise, whitening, and unwhitening are of course also possible. To produce the animated output, simply enter the command:
Note: The amplitude of the animated output initially builds up from zero to its nominal value over (approximately) the first 1.5 seconds. This ``turn-on'' transient is a consequence of the overlapping technique used by combine_data() to produce continuous-in-time detector output. (See the comment at the end of Section .)