|
| 1 | +{ |
| 2 | + "cells": [ |
| 3 | + { |
| 4 | + "cell_type": "markdown", |
| 5 | + "id": "34829d58-0d57-4e51-a072-85ba31ddae69", |
| 6 | + "metadata": { |
| 7 | + "editable": true, |
| 8 | + "slideshow": { |
| 9 | + "slide_type": "" |
| 10 | + }, |
| 11 | + "tags": [] |
| 12 | + }, |
| 13 | + "source": [ |
| 14 | + "# RF Network - One Port" |
| 15 | + ] |
| 16 | + }, |
| 17 | + { |
| 18 | + "cell_type": "markdown", |
| 19 | + "id": "a17a7d0b-3409-42db-9c73-928f1343e349", |
| 20 | + "metadata": {}, |
| 21 | + "source": [ |
| 22 | + "This is an example of a simulation of a Radio Frequency (RF) network with PathSim." |
| 23 | + ] |
| 24 | + }, |
| 25 | + { |
| 26 | + "cell_type": "raw", |
| 27 | + "id": "f7785b45-d223-4b21-9199-776db9bf9a47", |
| 28 | + "metadata": { |
| 29 | + "editable": true, |
| 30 | + "raw_mimetype": "text/x-rst", |
| 31 | + "slideshow": { |
| 32 | + "slide_type": "" |
| 33 | + }, |
| 34 | + "tags": [] |
| 35 | + }, |
| 36 | + "source": [ |
| 37 | + "In this example, we are using the block :class:`.RFNetwork` provided in PathSim to create the state-space model of an N-port RF network. This block uses the `scikit-rf <https://scikit-rf.readthedocs.io/en/latest/>`__ package to convert the frequency domain data into a state-space model. This conversion is performed using a `Vector Fitting <https://scikit-rf.readthedocs.io/en/latest/tutorials/VectorFitting.html>`__ method for fitting a rational function (model) to a set of frequency‐domain.\n" |
| 38 | + ] |
| 39 | + }, |
| 40 | + { |
| 41 | + "cell_type": "markdown", |
| 42 | + "id": "c9b536c4-9450-4b39-b719-a1f85f6f32b7", |
| 43 | + "metadata": { |
| 44 | + "editable": true, |
| 45 | + "slideshow": { |
| 46 | + "slide_type": "" |
| 47 | + }, |
| 48 | + "tags": [] |
| 49 | + }, |
| 50 | + "source": [ |
| 51 | + "Let's first make all the necessary import" |
| 52 | + ] |
| 53 | + }, |
| 54 | + { |
| 55 | + "cell_type": "code", |
| 56 | + "execution_count": null, |
| 57 | + "id": "489bad7b-a5a3-4a12-b57d-8464e02a220c", |
| 58 | + "metadata": { |
| 59 | + "editable": true, |
| 60 | + "slideshow": { |
| 61 | + "slide_type": "" |
| 62 | + }, |
| 63 | + "tags": [] |
| 64 | + }, |
| 65 | + "outputs": [], |
| 66 | + "source": [ |
| 67 | + "import matplotlib.pyplot as plt\n", |
| 68 | + "\n", |
| 69 | + "# Apply PathSim docs matplotlib style for consistent, theme-friendly figures\n", |
| 70 | + "plt.style.use('../pathsim_docs.mplstyle')\n", |
| 71 | + "\n", |
| 72 | + "from pathsim import Simulation, Connection\n", |
| 73 | + "from pathsim.blocks import Spectrum, GaussianPulseSource\n", |
| 74 | + "from pathsim.solvers import RKBS32\n", |
| 75 | + "\n", |
| 76 | + "from pathsim_rf import RFNetwork # requires the scikit-rf package to be installed" |
| 77 | + ] |
| 78 | + }, |
| 79 | + { |
| 80 | + "cell_type": "raw", |
| 81 | + "id": "143be8a6-51b1-45ad-ba2b-5bc06011ad07", |
| 82 | + "metadata": { |
| 83 | + "editable": true, |
| 84 | + "raw_mimetype": "text/restructuredtext", |
| 85 | + "slideshow": { |
| 86 | + "slide_type": "" |
| 87 | + }, |
| 88 | + "tags": [] |
| 89 | + }, |
| 90 | + "source": [ |
| 91 | + "The block :class:`.RFNetwork` takes as input either a `Touchstone file <https://en.wikipedia.org/wiki/Touchstone_file>`__ (.sNp file) or a scikit-rf `Network <https://scikit-rf.readthedocs.io/en/latest/api/network.html>`__. An N-port network has N inputs and N outputs.\n" |
| 92 | + ] |
| 93 | + }, |
| 94 | + { |
| 95 | + "cell_type": "code", |
| 96 | + "execution_count": null, |
| 97 | + "id": "d89dffe4-7717-44b5-aaf2-3c618a3fd282", |
| 98 | + "metadata": {}, |
| 99 | + "outputs": [], |
| 100 | + "source": [ |
| 101 | + "# The RF-Network block is created from a scikit-rf Network object example.\n", |
| 102 | + "# Here we use a frequency measurement example of a 1-port RF network (included in scikit-rf)\n", |
| 103 | + "import skrf as rf # for the example\n", |
| 104 | + "rfntwk = RFNetwork(rf.data.ring_slot_meas)" |
| 105 | + ] |
| 106 | + }, |
| 107 | + { |
| 108 | + "cell_type": "markdown", |
| 109 | + "id": "7dec1f58-7924-442d-9e91-d1719c31b947", |
| 110 | + "metadata": {}, |
| 111 | + "source": [ |
| 112 | + "Under the hood, scikit-rf performs a Vector Fitting of the frequency data and creates a PathSim State-Space model." |
| 113 | + ] |
| 114 | + }, |
| 115 | + { |
| 116 | + "cell_type": "raw", |
| 117 | + "id": "be668818-88e6-4648-8267-d11966f9cdda", |
| 118 | + "metadata": { |
| 119 | + "editable": true, |
| 120 | + "raw_mimetype": "text/restructuredtext", |
| 121 | + "slideshow": { |
| 122 | + "slide_type": "" |
| 123 | + }, |
| 124 | + "tags": [] |
| 125 | + }, |
| 126 | + "source": [ |
| 127 | + "In the following, we use a gaussian pulse to simulate the impulse response of the RF block. A spectrum analyzer (:class:`Spectrum`) is used to display the frequency response of the response. This frequency response is then compared to the original frequency data." |
| 128 | + ] |
| 129 | + }, |
| 130 | + { |
| 131 | + "cell_type": "code", |
| 132 | + "execution_count": null, |
| 133 | + "id": "e1308665-3910-44f5-8d63-a7a45881b388", |
| 134 | + "metadata": { |
| 135 | + "editable": true, |
| 136 | + "slideshow": { |
| 137 | + "slide_type": "" |
| 138 | + }, |
| 139 | + "tags": [] |
| 140 | + }, |
| 141 | + "outputs": [], |
| 142 | + "source": [ |
| 143 | + "# Gaussian pulse simulating an impulse response\n", |
| 144 | + "# Note that the scikit-rf Network object is passed as the 'network' parameter of the block,\n", |
| 145 | + "# which is convenient to access its frequency data.\n", |
| 146 | + "src = GaussianPulseSource(f_max=rfntwk.network.frequency.stop)\n", |
| 147 | + "\n", |
| 148 | + "# Spectrum analyser setup with the start and stop frequencies of the RF network\n", |
| 149 | + "spc = Spectrum(\n", |
| 150 | + " freq=rfntwk.network.f,\n", |
| 151 | + " labels=[\"pulse\", \"response\"]\n", |
| 152 | + ")" |
| 153 | + ] |
| 154 | + }, |
| 155 | + { |
| 156 | + "cell_type": "code", |
| 157 | + "execution_count": null, |
| 158 | + "id": "67f427af-deb1-417c-b602-2d454fac9489", |
| 159 | + "metadata": { |
| 160 | + "editable": true, |
| 161 | + "slideshow": { |
| 162 | + "slide_type": "" |
| 163 | + }, |
| 164 | + "tags": [] |
| 165 | + }, |
| 166 | + "outputs": [], |
| 167 | + "source": [ |
| 168 | + "# create the system connections and simulation setup\n", |
| 169 | + "sim = Simulation(\n", |
| 170 | + " blocks=[src, rfntwk, spc],\n", |
| 171 | + " connections=[\n", |
| 172 | + " Connection(src, rfntwk, spc[0]),\n", |
| 173 | + " Connection(rfntwk, spc[1])\n", |
| 174 | + " ],\n", |
| 175 | + " tolerance_lte_abs=1e-16, # this is due to the super tiny states\n", |
| 176 | + " tolerance_lte_rel=1e-5, # so error control is dominated by the relative truncation error\n", |
| 177 | + " Solver=RKBS32,\n", |
| 178 | + ")\n", |
| 179 | + "\n", |
| 180 | + "sim.run(1e-9)" |
| 181 | + ] |
| 182 | + }, |
| 183 | + { |
| 184 | + "cell_type": "markdown", |
| 185 | + "id": "d659c9e6-560d-4a40-a11d-cc00faf00e7d", |
| 186 | + "metadata": {}, |
| 187 | + "source": [ |
| 188 | + "Below, we compare the PathSim's frequency response to the original measurement data and to their Vector Fitted model calculated with scikit-rf. The Vector Fitted model and the PathSim's frequency response are in perfect agreement:" |
| 189 | + ] |
| 190 | + }, |
| 191 | + { |
| 192 | + "cell_type": "code", |
| 193 | + "execution_count": null, |
| 194 | + "id": "b2d1f099-c806-4c11-b588-ed5ab1ba12fc", |
| 195 | + "metadata": { |
| 196 | + "editable": true, |
| 197 | + "slideshow": { |
| 198 | + "slide_type": "" |
| 199 | + }, |
| 200 | + "tags": [] |
| 201 | + }, |
| 202 | + "outputs": [], |
| 203 | + "source": [ |
| 204 | + "# model frequency response H(f) recovered from the spectrum block\n", |
| 205 | + "freq, (G_pulse, G_filt) = spc.read()\n", |
| 206 | + "H_filt_sim = G_filt / G_pulse\n", |
| 207 | + "\n", |
| 208 | + "# plot the original S11 data, the vector-fitted model and the recovered frequency response\n", |
| 209 | + "fig, ax = plt.subplots()\n", |
| 210 | + "ax.plot(rfntwk.network.f/1e9, abs(rfntwk.network.s[:, 0, 0]), '.', label=\"S11 measurements\", alpha=0.5)\n", |
| 211 | + "ax.plot(freq/1e9, abs(rfntwk.vf.get_model_response(0, 0, freqs=freq)), lw=2, label=\"scikit-rf vector-fitting model\")\n", |
| 212 | + "ax.plot(freq/1e9, abs(H_filt_sim), '--', lw=2, label=\"pathsim impulse response\")\n", |
| 213 | + "ax.set_xlabel(\"Frequency [GHz]\")\n", |
| 214 | + "ax.set_ylabel(\"S11 magnitude\")\n", |
| 215 | + "ax.legend()\n", |
| 216 | + "plt.show()" |
| 217 | + ] |
| 218 | + } |
| 219 | + ], |
| 220 | + "metadata": { |
| 221 | + "kernelspec": { |
| 222 | + "display_name": "pathsim-rf", |
| 223 | + "language": "python", |
| 224 | + "name": "pathsim-rf" |
| 225 | + }, |
| 226 | + "language_info": { |
| 227 | + "codemirror_mode": { |
| 228 | + "name": "ipython", |
| 229 | + "version": 3 |
| 230 | + }, |
| 231 | + "file_extension": ".py", |
| 232 | + "mimetype": "text/x-python", |
| 233 | + "name": "python", |
| 234 | + "nbconvert_exporter": "python", |
| 235 | + "pygments_lexer": "ipython3", |
| 236 | + "version": "3.10.13" |
| 237 | + } |
| 238 | + }, |
| 239 | + "nbformat": 4, |
| 240 | + "nbformat_minor": 5 |
| 241 | +} |
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