.. _book_fig_chapter10_fig_LIGO_power_spectrum:


Plot the power spectrum of LIGO data
------------------------------------
Figure 10.6

LIGO data and its noise power spectrum. The upper panel shows a 2-second-long
stretch of data (~8000 points; essentially noise without signal) from LIGO
Hanford. The middle and bottom panels show the power spectral density computed
for 2048 seconds of data, sampled at 4096 Hz (~8 million data values). The gray
line shows the PSD computed using a naive FFT approach; the dark line uses
Welch's method of overlapping windows to smooth noise; the middle panel uses a
1-second-wide top-hat window and the bottom panel the so-called Hanning
(cosine) window with the same width.



.. image:: ../images/chapter10/fig_LIGO_power_spectrum_1.png
    :scale: 100
    :align: center


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