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  {
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   "source": [
    "# Lumped element filter design\n",
    "\n",
    "This example shows how to use PyAEDT to use the ``FilterSolutions`` module to design and\n",
    "visualize the frequency response of a band-pass Butterworth filter.\n",
    "\n",
    "Keywords: **filter solutions**"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "723e9751",
   "metadata": {},
   "source": [
    "## Perform imports and define constants\n",
    "\n",
    "Perform required imports."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "c6b4e88f",
   "metadata": {},
   "outputs": [],
   "source": [
    "import ansys.aedt.core\n",
    "import matplotlib.pyplot as plt\n",
    "from ansys.aedt.core.filtersolutions_core.attributes import (\n",
    "    FilterClass, FilterImplementation, FilterType)\n",
    "from ansys.aedt.core.filtersolutions_core.ideal_response import \\\n",
    "    FrequencyResponseColumn"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "00b1c5c5",
   "metadata": {},
   "source": [
    "Define constants."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "47713f12",
   "metadata": {},
   "outputs": [],
   "source": [
    "AEDT_VERSION = \"2025.1\""
   ]
  },
  {
   "cell_type": "markdown",
   "id": "cc0490bc",
   "metadata": {
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   },
   "source": [
    "## Define function used for plotting\n",
    "\n",
    "Define formal plot function."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "9b4f3661",
   "metadata": {},
   "outputs": [],
   "source": [
    "def format_plot():\n",
    "    plt.xlabel(\"Frequency (Hz)\")\n",
    "    plt.ylabel(\"Magnitude S21 (dB)\")\n",
    "    plt.title(\"Ideal Frequency Response\")\n",
    "    plt.xscale(\"log\")\n",
    "    plt.legend()\n",
    "    plt.grid()"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "b07892b2",
   "metadata": {},
   "source": [
    "## Create lumped filter design\n",
    "\n",
    "Create a lumped element filter design and assign the class, type, frequency, and order."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "3dc689f1",
   "metadata": {},
   "outputs": [],
   "source": [
    "design = ansys.aedt.core.FilterSolutions(\n",
    "    version=AEDT_VERSION, implementation_type=FilterImplementation.LUMPED\n",
    ")\n",
    "design.attributes.filter_class = FilterClass.BAND_PASS\n",
    "design.attributes.filter_type = FilterType.BUTTERWORTH\n",
    "design.attributes.pass_band_center_frequency = \"1G\"\n",
    "design.attributes.pass_band_width_frequency = \"500M\"\n",
    "design.attributes.filter_order = 5"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "6d0931eb",
   "metadata": {},
   "source": [
    "## Plot frequency response of filter\n",
    "\n",
    "Plot the frequency response of the filter without any transmission zeros."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "72e89c53",
   "metadata": {},
   "outputs": [],
   "source": [
    "freq, mag_db = design.ideal_response.frequency_response(\n",
    "    FrequencyResponseColumn.MAGNITUDE_DB\n",
    ")\n",
    "plt.plot(freq, mag_db, linewidth=2.0, label=\"Without Tx Zero\")\n",
    "format_plot()\n",
    "plt.show()"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "b3bea45b",
   "metadata": {},
   "source": [
    "## Add a transmission zero to filter design\n",
    "\n",
    "Add a transmission zero that yields nulls separated by two times the pass band width (1 GHz).\n",
    "Plot the frequency response of the filter with the transmission zero."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "ab56d241",
   "metadata": {},
   "outputs": [],
   "source": [
    "design.transmission_zeros_ratio.append_row(\"2.0\")\n",
    "freq_with_zero, mag_db_with_zero = design.ideal_response.frequency_response(\n",
    "    FrequencyResponseColumn.MAGNITUDE_DB\n",
    ")\n",
    "plt.plot(freq, mag_db, linewidth=2.0, label=\"Without Tx Zero\")\n",
    "plt.plot(freq_with_zero, mag_db_with_zero, linewidth=2.0, label=\"With Tx Zero\")\n",
    "format_plot()\n",
    "plt.show()"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "7b05671d",
   "metadata": {},
   "source": [
    "## Generate netlist for designed filter\n",
    "\n",
    "Generate and print the netlist for the designed filter with the added transmission zero to\n",
    "the filter."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "86e2f3aa",
   "metadata": {},
   "outputs": [],
   "source": [
    "netlist = design.topology.circuit_response()\n",
    "print(\"Netlist: \\n\", netlist)"
   ]
  }
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