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{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Chapter12 - Fiber-optic communiation systems"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 12.1 : Page 299"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"maximum possible link length = 8.00 km\n",
"total rise time of the system in ns is 30.0\n"
]
}
],
"source": [
"from __future__ import division\n",
"from math import sqrt, pi\n",
"#link length and reise time\n",
"af=2.5##dB/km\n",
"ac=0.5##dB/splice\n",
"nc=1##\n",
"lc=1##dB\n",
"ncc=2##\n",
"plx=-10##dBm\n",
"prx=-42##dBm\n",
"Ms=6##dB\n",
"L=((plx-prx-Ms-(lc*ncc))/(af+ac))##\n",
"TTX=12##NS\n",
"TRX=11##NS\n",
"NS1=3##NS/KM\n",
"NS2=1##NS/KM\n",
"tmat=(NS1*L)##ns\n",
"tint=(NS2*L)##ns\n",
"tsys=sqrt((TTX**2+tmat**2+tint**2+TRX**2))##ns\n",
"print\"maximum possible link length = %0.2f km\"% L\n",
"print \"total rise time of the system in ns is\",round(tsys)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 12.2: Page 305"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"part (a)\n",
"maximum possible link length = 4.71 km\n",
"part (b)\n",
"system bandwidth = 8.00 MHz\n"
]
}
],
"source": [
"## link length and bandwidth\n",
"print \"part (a)\"\n",
"af=3##dB/km\n",
"ac=0.5##dB/splice\n",
"nc=1##\n",
"lc=1##dB\n",
"ncc=1.5##\n",
"plx=0##dBm\n",
"prx=-25##dBm\n",
"Ms=7##dB\n",
"L=((plx-prx-Ms-(lc*ncc))/(af+ac))##\n",
"TTX=12##NS\n",
"TRX=11##NS\n",
"NS1=3##NS/KM\n",
"NS2=1##NS/KM\n",
"tmat=(NS1*L)##ns\n",
"tint=(NS2*L)##ns\n",
"tsys=sqrt((TTX**2+tmat**2+tint**2+TRX**2))##ns\n",
"print \"maximum possible link length = %0.2f km\"%L\n",
"print \"part (b)\"\n",
"af=3##dB/km\n",
"ac=0.5##dB/splice\n",
"nc=1##\n",
"lc=1##dB\n",
"ncc=1.5##\n",
"plx=-0##dBm\n",
"prx=-25##dBm\n",
"Ms=7##dB\n",
"L=((plx-prx-Ms-(lc*ncc))/(af+ac))##\n",
"TTX=1##NS\n",
"TRX=5##NS\n",
"NS1=9##NS/KM\n",
"NS2=2##NS/KM\n",
"tf=((NS1*L)**2+(NS2*L)**2)##\n",
"tsys=sqrt((TTX**2+tf+TRX**2))##ns\n",
"df=0.35/(tsys*10**-3)##\n",
"print \"system bandwidth = %0.2f MHz\"%round(df)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 12.3 : Page 310"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"no. of subscribers are 38.0\n"
]
}
],
"source": [
"from math import log10\n",
"#no. of subscribers\n",
"pt=1##mW\n",
"pn=-40##dBm\n",
"pn1=10**(pn/10)##\n",
"c=0.05##\n",
"d=0.11##\n",
"x=((pn1)/(pt*c))##\n",
"y=((log10(x))/(log10((1-d)*(1-c))))##\n",
"n=y+1##\n",
"print \"no. of subscribers are\",round(n)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 12.4: Page 311"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Total power, P_tot = 92.4 mW\n"
]
}
],
"source": [
"# Total power\n",
"#given data :\n",
"L_eff=20## in km\n",
"del_lamdaC=125## in nm\n",
"gR=6*10**-14## m/W\n",
"A_eff=55*10**-12## in m**2#\n",
"del_lamdaS=0.8## in nm\n",
"N=32## number of channels\n",
"F=0.1## constant\n",
"P_tot=(4*F*del_lamdaC*A_eff)/(gR*del_lamdaS*L_eff*(N-1))#\n",
"print \"Total power, P_tot = %0.1f mW\"%P_tot"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 12.5 : Page 312"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"SBS threshold power for the worst case = 8.66 mW\n",
"SBS threshold power for the best possible case = 17.33 mW\n"
]
}
],
"source": [
"#SBS threshold power\n",
"#given data :\n",
"gb=4*10**-11## in m/W\n",
"A_eff=55*10**-12## in m**2\n",
"L_eff=20## in km\n",
"lamda_p=1.55## micro-m\n",
"n=1.46## constant\n",
"Va=5960## for the silica fiber in m-s**-1\n",
"Vb=(2*n*Va)/lamda_p#\n",
"del_v=100*10**6## in Hz\n",
"del_Vb=20*10**6## in Hz\n",
"b1=1#\n",
"b2=2#\n",
"P_th=((21*b1*A_eff)/(gb*L_eff))*(1+(del_v/del_Vb))\n",
"P_th1=((21*b2*A_eff)/(gb*L_eff))*(1+(del_v/del_Vb))\n",
"print \"SBS threshold power for the worst case = %0.2f mW\"%P_th\n",
"print \"SBS threshold power for the best possible case = %0.2f mW\"%P_th1"
]
}
],
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"kernelspec": {
"display_name": "Python 2",
"language": "python",
"name": "python2"
},
"language_info": {
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"file_extension": ".py",
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"name": "python",
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|
