path: root/Electronic_Communication_Systems_by_Roy_Blake/Chapter24.ipynb

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   "source": [
    "# Chapter 24 : Fiber Optics"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 3 : pg 888"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
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     "text": [
      "The core diameter is 4.18746666667e-06 m\n"
     ]
    }
   ],
   "source": [
    " \n",
    "# page no 888\n",
    "# prob no 24.3\n",
    "#calculate the core diameter\n",
    "#given\n",
    "NA=0.15;\n",
    "wl=820*10**-9;#in m\n",
    "#calculations\n",
    "d_core=2*(0.383*wl/NA);\n",
    "#results\n",
    "print 'The core diameter is',d_core,'m'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 4 : pg 890"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
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   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The maximun distance that can be use between repeaters is 5.88 km\n"
     ]
    }
   ],
   "source": [
    " \n",
    "# page no 890\n",
    "# prob no 24.4\n",
    "#calculate the max distance\n",
    "#given\n",
    "Bl=500;#in MHz-km\n",
    "B=85.;#in MHz\n",
    "#calculations\n",
    "# By using Bandwidth-distance product formula\n",
    "l=Bl/B;\n",
    "#results\n",
    "print 'The maximun distance that can be use between repeaters is',round(l,2),'km'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 5 : pg 891"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
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   },
   "outputs": [
    {
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     "output_type": "stream",
     "text": [
      "The total dispersion is 948.95 ps\n"
     ]
    }
   ],
   "source": [
    " \n",
    "# page no 891\n",
    "# prob no 24.5\n",
    "#calculate the total dispersion\n",
    "#given\n",
    "wl0=1310.;#in ns\n",
    "So=0.05;#in ps/(nm**2*km)\n",
    "l=50.;#in km\n",
    "wl=1550.;#in ns\n",
    "d=2.;#in nm\n",
    "#calculations\n",
    "# Chromatic dispersion is given as\n",
    "Dc=(So/4)*(wl-(wl0**4/wl**3));\n",
    "# Dispersion is\n",
    "D=Dc*d;\n",
    "# Therefore total dispersion is \n",
    "dt=D*l;\n",
    "#results\n",
    "print 'The total dispersion is',round(dt,2),'ps'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 6 : pg 893"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The bandwidth distance product is 26343519494.2 Hz-km\n"
     ]
    }
   ],
   "source": [
    " \n",
    "# page no 893\n",
    "# prob no 24.6\n",
    "#given\n",
    "#calculate the bandwidth distance product\n",
    "#Refer problem 24.5\n",
    "dt=949*10**-12;#in sed\n",
    "l=50.;#in km\n",
    "#calculations\n",
    "B=1/(2*dt);\n",
    "#By using Bandwidth-distance product formula\n",
    "Bl= B*l;\n",
    "#results\n",
    "print 'The bandwidth distance product is',Bl,'Hz-km'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 7 : pg 899"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
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   },
   "outputs": [
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     "text": [
      "a) The proportion of input power emerging at port 2 is 10.0 %\n",
      "b) The proportion of input power emerging at port 3 is 10.0 %\n",
      "Directivity is 40 dB\n",
      "the excess loss is 6.99 dB\n"
     ]
    }
   ],
   "source": [
    " \n",
    "# page no 899\n",
    "# prob no 24.7\n",
    "#calculate the directivity, power, excess loss\n",
    "#given\n",
    "from math import log10\n",
    "# refer table from the problem page no 899\n",
    "P_coupling1 =-3; P_coupling2 = -6; P_coupling3 =-40;# in dB\n",
    "#calculations and results\n",
    "#Part a) The proportion of input power emerging at port 2\n",
    "P2_Pin=10**(P_coupling1/10);\n",
    "print 'a) The proportion of input power emerging at port 2 is',P2_Pin*100,'%'\n",
    "P3_Pin=10**(P_coupling2/10);\n",
    "print 'b) The proportion of input power emerging at port 3 is',P3_Pin*100,'%'\n",
    "# Part b) In the reverse direction,the signal is 40dB down for all combinations, so\n",
    "directivity = 40;\n",
    "print 'Directivity is',directivity,'dB'\n",
    "Pin_total = P2_Pin + P3_Pin;\n",
    "# excess loss in dB\n",
    "loss=-10*log10(Pin_total);\n",
    "print 'the excess loss is',round(loss,2),'dB'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 8 : pg 901"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The energy of photon in eV is 1.242375 eV\n"
     ]
    }
   ],
   "source": [
    " \n",
    "# page no 901\n",
    "# prob no 24.8\n",
    "#calculate the energy of photon\n",
    "#given\n",
    "wl=1*10**-6;\n",
    "c= 3*10**8;\n",
    "h=6.626*10**-34\n",
    "#calculations\n",
    "f=c/wl;\n",
    "E=h*f;# in Joule\n",
    "#this energy can be converted into electron-volt. we know 1eV=1.6*10**-19 J\n",
    "eV=1.6*10**-19 ;\n",
    "E_ev=E/eV;\n",
    "#results\n",
    "print 'The energy of photon in eV is',E_ev,'eV'"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example 9 : pg 909"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The diode current is 165.0 nA\n"
     ]
    }
   ],
   "source": [
    " \n",
    "# page no 909\n",
    "# prob no 24_9\n",
    "#calculate the diode current\n",
    "#given\n",
    "# refer fig 24.25\n",
    "P_in=500;Responsivity=0.33;\n",
    "#calculations\n",
    "I_d = P_in * Responsivity;\n",
    "#results\n",
    "print 'The diode current is',I_d,'nA'"
   ]
  }
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