port</span> <span class="nn">matplotlib.pyplot</span> <span class="k">as</span> <span class="nn">plt</span>
<span class="kn">import</span> <span class="nn">scipy.special</span> <span class="k">as</span> <span class="nn">ss</span>
<span class="kn">from</span> <span class="nn">vtools.functions.filter</span> <span class="kn">import</span> <span class="n">butterworth</span><span class="p">,</span> <span class="n">cosine_lanczos</span>

<span class="c1"># Frequency, amplitude, phase of semidiurnal tide</span>
<s