{
  "nbformat_minor": 0, 
  "nbformat": 4, 
  "cells": [
    {
      "execution_count": null, 
      "cell_type": "code", 
      "source": [
        "%matplotlib inline"
      ], 
      "outputs": [], 
      "metadata": {
        "collapsed": false
      }
    }, 
    {
      "source": [
        "\n# Show noise levels from empty room data\n\n\nThis shows how to use :meth:`mne.io.Raw.plot_psd` to examine noise levels\nof systems. See [1]_ for an example.\n\nReferences\n----------\n.. [1] Khan S, Cohen D (2013). Note: Magnetic noise from the inner wall of\n   a magnetically shielded room. Review of Scientific Instruments 84:56101.\n   https://doi.org/10.1063/1.4802845\n\n"
      ], 
      "cell_type": "markdown", 
      "metadata": {}
    }, 
    {
      "execution_count": null, 
      "cell_type": "code", 
      "source": [
        "# Author: Eric Larson <larson.eric.d@gmail.com>\n#\n# License: BSD (3-clause)\n\nimport os.path as op\nimport mne\n\ndata_path = mne.datasets.sample.data_path()\n\nraw_erm = mne.io.read_raw_fif(op.join(data_path, 'MEG', 'sample',\n                                      'ernoise_raw.fif'), preload=True)"
      ], 
      "outputs": [], 
      "metadata": {
        "collapsed": false
      }
    }, 
    {
      "source": [
        "We can plot the absolute noise levels:\n\n"
      ], 
      "cell_type": "markdown", 
      "metadata": {}
    }, 
    {
      "execution_count": null, 
      "cell_type": "code", 
      "source": [
        "raw_erm.plot_psd(tmax=10., average=True, dB=False, xscale='log')"
      ], 
      "outputs": [], 
      "metadata": {
        "collapsed": false
      }
    }
  ], 
  "metadata": {
    "kernelspec": {
      "display_name": "Python 2", 
      "name": "python2", 
      "language": "python"
    }, 
    "language_info": {
      "mimetype": "text/x-python", 
      "nbconvert_exporter": "python", 
      "name": "python", 
      "file_extension": ".py", 
      "version": "2.7.13", 
      "pygments_lexer": "ipython2", 
      "codemirror_mode": {
        "version": 2, 
        "name": "ipython"
      }
    }
  }
}