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

    Click :ref:`here <sphx_glr_download_auto_examples_plot_1_3_1_noisy_chirp_spectrum.py>` to download the full example code
.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_examples_plot_1_3_1_noisy_chirp_spectrum.py:


================================
Energy Spectrum of a Noisy Chirp
================================

Generate a noisy chirp and plot its energy spectrum.

Figure 1.5 from the tutorial.



.. image:: /auto_examples/images/sphx_glr_plot_1_3_1_noisy_chirp_spectrum_001.png
    :class: sphx-glr-single-img





.. code-block:: default


    from tftb.generators import fmlin, sigmerge, noisecg
    import matplotlib.pyplot as plt
    import numpy as np

    # Generate a chirp signal

    n_points = 128
    fmin, fmax = 0.0, 0.5

    signal, _ = fmlin(n_points, fmin, fmax)

    # Noisy chirp

    noisy_signal = sigmerge(signal, noisecg(128), 0)

    # Enery spectrum of the noisy chirp.

    dsp1 = np.fft.fftshift(np.abs(np.fft.fft(noisy_signal)) ** 2)
    plt.plot(np.arange(-64, 64, dtype=float) / 128.0, dsp1)
    plt.xlim(-0.5, 0.5)
    plt.title('Spectrum of Noisy Chirp')
    plt.ylabel('Squared modulus')
    plt.xlabel('Normalized Frequency')
    plt.grid()
    plt.show()


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

   **Total running time of the script:** ( 0 minutes  0.164 seconds)


.. _sphx_glr_download_auto_examples_plot_1_3_1_noisy_chirp_spectrum.py:


.. only :: html

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



  .. container:: sphx-glr-download

     :download:`Download Python source code: plot_1_3_1_noisy_chirp_spectrum.py <plot_1_3_1_noisy_chirp_spectrum.py>`



  .. container:: sphx-glr-download

     :download:`Download Jupyter notebook: plot_1_3_1_noisy_chirp_spectrum.ipynb <plot_1_3_1_noisy_chirp_spectrum.ipynb>`


.. only:: html

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

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