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

    Click :ref:`here <sphx_glr_download_auto_examples_plot_1_3_3_transient_spectrogram.py>` to download the full example code
.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_examples_plot_1_3_3_transient_spectrogram.py:


=======================================
Spectrogram of a Noisy Transient Signal
=======================================

This example demonstrates the simple use of a Spectrogram to localize a signal
in time and frequency. The transient signal appears at the normalized frequency
0.25 and between time points 125 and 160.

Figure 1.11 from the tutorial.



.. image:: /auto_examples/images/sphx_glr_plot_1_3_3_transient_spectrogram_001.png
    :class: sphx-glr-single-img





.. code-block:: default



    import numpy as np
    from scipy.signal import hamming
    from tftb.generators import amexpos, fmconst, sigmerge, noisecg
    from tftb.processing.cohen import Spectrogram

    # Generate a noisy transient signal.
    transsig = amexpos(64, kind='unilateral') * fmconst(64)[0]
    signal = np.hstack((np.zeros((100,)), transsig, np.zeros((92,))))
    signal = sigmerge(signal, noisecg(256), -5)

    fwindow = hamming(65)
    spec = Spectrogram(signal, n_fbins=128, fwindow=fwindow)
    spec.run()
    spec.plot(kind="contour", threshold=0.1, show_tf=False)


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

   **Total running time of the script:** ( 0 minutes  0.177 seconds)


.. _sphx_glr_download_auto_examples_plot_1_3_3_transient_spectrogram.py:


.. only :: html

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



  .. container:: sphx-glr-download

     :download:`Download Python source code: plot_1_3_3_transient_spectrogram.py <plot_1_3_3_transient_spectrogram.py>`



  .. container:: sphx-glr-download

     :download:`Download Jupyter notebook: plot_1_3_3_transient_spectrogram.ipynb <plot_1_3_3_transient_spectrogram.ipynb>`


.. only:: html

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

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