{
  "cells": [
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "%matplotlib inline"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\n# Create and Plot Signals\n\n\nCreate and plot signals / noise; combine them at a specific SNR.\n\nTo see how soundpy implements this, see `soundpy.dsp.generate_sound`, \n`soundpy.dsp.generate_noise` and `soundpy.dsp.add_backgroundsound`.\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Let's import soundpy\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "import soundpy as sp"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Create a Signal\n^^^^^^^^^^^^^^^\n\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "First let's set what sample rate we want to use\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "sr = 44100"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Let's create a signal of 10 Hz \n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "sig1_hz = 10\nsig1, sr = sp.generate_sound(freq=sig1_hz, amplitude = 0.4, sr=sr, dur_sec=1)\nsp.plotsound(sig1, sr=sr, feature_type = 'signal',\n               title = 'Signal: {} Hz'.format(sig1_hz), subprocess=True)"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Let's create a signal of 20 Hz\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "sig2_hz = 20 \nsig2, sr = sp.generate_sound(freq=sig2_hz, amplitude= 0.4, sr=sr, dur_sec=1)\nsp.plotsound(sig2, sr=sr, feature_type = 'signal',\n               title = 'Signal: {} Hz'.format(sig2_hz), subprocess=True)"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Combine Signals \n^^^^^^^^^^^^^^^\n\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Add them together and see what they look like:\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "sig3 = sig1 + sig2\nsp.plotsound(sig3, sr=sr, feature_type = 'signal', \n               title='Mixed Signals: {} Hz + {} Hz'.format(sig1_hz, sig2_hz), \n               subprocess=True)"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Generate Pseudo-Random Noise\n^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Create noise to add to the signal:\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "noise = sp.generate_noise(len(sig3), amplitude=0.02, random_seed=40)\nsp.plotsound(noise, sr=sr, feature_type = 'signal',\n               title='Random Noise', subprocess=True)"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Control SNR: Adding a Background Sound\n^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Add noise at signal-to-noise ratio of 40\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "sig_noisy, snr = sp.dsp.add_backgroundsound(\n    audio_main = sig3, \n    audio_background = noise, \n    sr = sr,\n    snr = 40,\n    clip_at_zero = False)\n\n# keep energy between 1 and -1 \nsig_noisy = sp.dsp.scalesound(sig_noisy, max_val=1)\nsp.plotsound(sig_noisy, sr=sr, feature_type = 'signal', title='Signal + Noise: 40 SNR',\n             subprocess=True)"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Add noise at signal-to-noise ratio of 20\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "sig_noisy, snr = sp.dsp.add_backgroundsound(\n    audio_main = sig3, \n    audio_background = noise,\n    sr = sr,\n    snr = 20)\n# keep energy between 1 and -1 \nsig_noisy = sp.dsp.scalesound(sig_noisy, max_val=1)\nsp.plotsound(sig_noisy, sr=sr, feature_type = 'signal', title='Signal + Noise: 20 SNR',\n             subprocess=True)"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Add noise at signal-to-noise ratio of 10\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "sig_noisy, snr = sp.dsp.add_backgroundsound(\n    audio_main = sig3, \n    audio_background = noise,\n    sr = sr,\n    snr = 10)\n# keep energy between 1 and -1 \nsig_noisy = sp.dsp.scalesound(sig_noisy, max_val=1)\nsp.plotsound(sig_noisy, sr=sr, feature_type = 'signal', title='Signal + Noise: 10 SNR',\n             subprocess=True)"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Add noise at signal-to-noise ratio of 0\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "sig_noisy, snr = sp.dsp.add_backgroundsound(\n    audio_main = sig3,\n    audio_background = noise,\n    sr = sr,\n    snr = 0)\n# keep energy between 1 and -1 \nsig_noisy = sp.dsp.scalesound(sig_noisy, max_val=1)\nsp.plotsound(sig_noisy, sr=sr, feature_type = 'signal', title='Signal + Noise: 0 SNR',\n             subprocess=True)"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Add noise at signal-to-noise ratio of -10\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "sig_noisy, snr = sp.dsp.add_backgroundsound(\n    audio_main = sig3, \n    audio_background = noise,\n    sr = sr,\n    snr = -10)\n# keep energy between 1 and -1 \nsig_noisy = sp.dsp.scalesound(sig_noisy, max_val=1)\nsp.plotsound(sig_noisy, sr=sr, feature_type = 'signal', title='Signal + Noise: -10 SNR',\n             subprocess=True)"
      ]
    }
  ],
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