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  {
   "cell_type": "markdown",
   "id": "bcd07c1e-6722-44c7-b162-267f1341c2fe",
   "metadata": {},
   "source": [
    "# Standard filterbank frequency response and impulse response"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "f0c4d6ef-69b2-4b5c-92fd-d987a11f3cbd",
   "metadata": {},
   "outputs": [],
   "source": [
    "# Prerequisites, uncomment below in case of errors. Also for ipympl, restart Jupyter Lab if it was not installed\n",
    "\n",
    "!cd .. && maturin develop -F python-bindings\n",
    "#!pip install ipympl scipy matplotlib"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "23b45cf6-85bc-4eaa-8f27-77c5b354e772",
   "metadata": {},
   "outputs": [],
   "source": [
    "# If this does not work, install ipympl and reboot Jupyter Lab\n",
    "%matplotlib widget"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "96090ac9-2033-411d-8e45-0c6b375a268b",
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np\n",
    "import matplotlib.pyplot as plt\n",
    "from numpy import log10\n",
    "from lasprs import StandardFilterDescriptor\n",
    "def level(a):\n",
    "    return 20*np.log10(np.abs(a))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "52343e3d-63ef-4fc2-ad7e-85ca124efdac",
   "metadata": {},
   "outputs": [],
   "source": [
    "freq = np.logspace(log10(2), log10(2e4), 200)\n",
    "octaves = StandardFilterDescriptor.genFilterSetInRange(1, 10, 16e3, False)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "2788f062-34ab-4573-9849-459fdccc97d3",
   "metadata": {},
   "outputs": [],
   "source": [
    "hs = [ o.genFilter().tf(0,freq) for o in octaves]\n",
    "names = [str(o) for o in octaves]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "3366f635-29fe-4757-ab0c-9d4929f8cddb",
   "metadata": {},
   "outputs": [],
   "source": [
    "plt.figure()\n",
    "# plt.subplot(211)\n",
    "plt.title('Frequency response of filters - magnitude')\n",
    "\n",
    "for h in hs:\n",
    "    plt.semilogx(freq, level(h))\n",
    "plt.legend(names)\n",
    "plt.ylabel('Magnitude [dB]')\n",
    "plt.ylim(-50, 1)\n",
    "plt.xlabel('Freq. [Hz]')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "b242187a-3449-4c30-8e26-28e75d59c414",
   "metadata": {},
   "outputs": [],
   "source": [
    "fs = 48000\n",
    "tend = 0.01\n",
    "t = np.linspace(0, tend, int(tend*fs), endpoint=False)\n",
    "impulse = np.zeros(t.size)\n",
    "impulse[0] = 1\n",
    "plt.figure()\n",
    "plt.title('Filter impulse response')\n",
    "for o in octaves:\n",
    "    i = o.genFilter().bilinear(fs).filter(impulse)\n",
    "    plt.plot(t, i)\n",
    "plt.legend(names, loc='upper right')\n",
    "plt.ylabel('Filter output [-]')\n",
    "plt.xlabel('Time [s]')"
   ]
  }
 ],
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