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

.. only:: html

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

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

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

.. _sphx_glr_examples_arbitrarymagnitude.py:


=======================================
FIR filter with magnitude from function.
=======================================

.. GENERATED FROM PYTHON SOURCE LINES 6-15

.. code-block:: Python


    import math

    import matplotlib.pyplot as plt
    from mplsignal import freqz_fir

    from fird.designer import FIRDesigner
    from fird.objective import FunctionLinearObjective








.. GENERATED FROM PYTHON SOURCE LINES 16-17

First, design a filter minimizing the approximation error when approximating cos in the range 0 to 0.3π.

.. GENERATED FROM PYTHON SOURCE LINES 17-26

.. code-block:: Python

    o = FunctionLinearObjective([0, 0.3], lambda f: (1 - math.sin(f * math.pi)))
    d = FIRDesigner(15, o)
    d.solve()
    fig, ax = plt.subplots()
    freqz_fir(d.get_impulse_response(), ax=ax, magnitude_scale="linear", style="magnitude")
    o.plot(ax, label="Desired")
    ax.legend()
    fig.show()




.. image-sg:: /examples/images/sphx_glr_arbitrarymagnitude_001.png
   :alt: arbitrarymagnitude
   :srcset: /examples/images/sphx_glr_arbitrarymagnitude_001.png
   :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 27-29

To avoid that the magnitude becomes large in the band that we do not care about,
add a constraint.

.. GENERATED FROM PYTHON SOURCE LINES 29-40

.. code-block:: Python


    from fird.constraint import PiecewiseLinearConstraint  # noqa: E402

    c = PiecewiseLinearConstraint([0.3, 1], [0, 0], [1])
    d = FIRDesigner(15, o, c)
    d.solve()
    fig, ax = plt.subplots()
    freqz_fir(d.get_impulse_response(), ax=ax, magnitude_scale="linear", style="magnitude")
    o.plot(ax, label="Desired")
    ax.legend()
    fig.show()



.. image-sg:: /examples/images/sphx_glr_arbitrarymagnitude_002.png
   :alt: arbitrarymagnitude
   :srcset: /examples/images/sphx_glr_arbitrarymagnitude_002.png
   :class: sphx-glr-single-img






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

   **Total running time of the script:** (0 minutes 0.287 seconds)


.. _sphx_glr_download_examples_arbitrarymagnitude.py:

.. only:: html

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

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

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

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

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

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

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


.. only:: html

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

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