.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "examples/frequencyseries/transfer_function.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_examples_frequencyseries_transfer_function.py>`
        to download the full example code.

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_examples_frequencyseries_transfer_function.py:


.. sectionauthor:: Duncan Macleod <duncan.macleod@ligo.org>
.. currentmodule:: gwpy.timeseries

Transfer function
#################

In this example we demonstrate how to calculate the transfer function
between two `TimeSeries` signals.

All ground-based gravitational wave observatories would be unable to
operate if they did not employ sophisticated ground-motion suppression
technology to prevent vibrations from the local (or remote) environment
from transferring through to optical components.

The impact of the seismic isolation system can be seen by calculating
the transfer function between the ground motion at the laboratory
and that of the optical suspension points.

.. GENERATED FROM PYTHON SOURCE LINES 38-43

.. code-block:: Python


    from gwpy.time import tconvert
    from gwpy.timeseries import TimeSeriesDict
    from gwpy.plot import BodePlot








.. GENERATED FROM PYTHON SOURCE LINES 44-45

For this example we will use data from the |GWOSC_AUX_RELEASE|_:

.. GENERATED FROM PYTHON SOURCE LINES 45-51

.. code-block:: Python


    start = tconvert("August 14 2017 10:25")
    end = start + 1800
    gndchannel = "L1:ISI-GND_STS_ITMY_Y_DQ"
    suschannel = "L1:ISI-ITMY_SUSPOINT_ITMY_EUL_L_DQ"








.. GENERATED FROM PYTHON SOURCE LINES 52-54

We can call the :meth:`~TimeSeriesDict.get` method of the `TimeSeriesDict`
to retrieve all data in a single operation:

.. GENERATED FROM PYTHON SOURCE LINES 54-63

.. code-block:: Python

    data = TimeSeriesDict.get(
        [gndchannel, suschannel],
        start,
        end,
        host="nds.gwosc.org",
    )
    gnd = data[gndchannel]
    sus = data[suschannel]








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The transfer function between time series is easily computed with the
:meth:`~TimeSeries.transfer_function` method:

.. GENERATED FROM PYTHON SOURCE LINES 66-68

.. code-block:: Python

    tf = gnd.transfer_function(sus, fftlength=128, overlap=64)








.. GENERATED FROM PYTHON SOURCE LINES 69-71

The `~gwpy.plot.BodePlot` knows how to separate a complex-valued
`~gwpy.frequencyseries.FrequencySeries` into magnitude and phase:

.. GENERATED FROM PYTHON SOURCE LINES 71-81

.. code-block:: Python

    plot = BodePlot(tf)
    plot.maxes.set_title(
        r"L1 ITMY ground $\rightarrow$ SUS transfer function",
    )
    plot.maxes.set_xlim(5e-2, 30)
    plot.show()

    # This example demonstrates the impressive noise suppression of the LIGO
    # seismic isolation system. For more details, please see
    # https://www.ligo.caltech.edu/page/vibration-isolation.



.. image-sg:: /examples/frequencyseries/images/sphx_glr_transfer_function_001.png
   :alt: L1 ITMY ground $\rightarrow$ SUS transfer function
   :srcset: /examples/frequencyseries/images/sphx_glr_transfer_function_001.png
   :class: sphx-glr-single-img






.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 2.120 seconds)


.. _sphx_glr_download_examples_frequencyseries_transfer_function.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: transfer_function.ipynb <transfer_function.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: transfer_function.py <transfer_function.py>`

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: transfer_function.zip <transfer_function.zip>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_