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diff --git a/backup/Optical_Communiation_by_Anasuya_Kalavar_version_backup/chapter8.ipynb b/backup/Optical_Communiation_by_Anasuya_Kalavar_version_backup/chapter8.ipynb new file mode 100755 index 00000000..11017e30 --- /dev/null +++ b/backup/Optical_Communiation_by_Anasuya_Kalavar_version_backup/chapter8.ipynb @@ -0,0 +1,272 @@ +{ + "metadata": { + "name": "", + "signature": "sha256:3deb63e976713f6e36585549e6b144389b0fc28fe2982a2838d929f3804cde18" + }, + "nbformat": 3, + "nbformat_minor": 0, + "worksheets": [ + { + "cells": [ + { + "cell_type": "heading", + "level": 1, + "metadata": {}, + "source": [ + "chapter8 - Optical receiver operation" + ] + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.2.1, page 8-6" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from __future__ import division\n", + "from numpy import log, sqrt, pi, log10\n", + "P=10**-9 #probability of error\n", + "eta=1 #ideal detector\n", + "h=6.626*10**-34 #plank's constant\n", + "c=3*10**8 #speed of light\n", + "lamda=1*10**-6 #wavelength\n", + "B=10**7 #bit rate\n", + "Mn = -log(P) \n", + "print \"The quantum limit at the receiver to maintain bit error rate 10**-9 is (%.1f*h*f)/eta.\" %Mn\n", + "f=c/lamda\n", + "Popt= 0.5*Mn*h*f*B/eta #computing optical power\n", + "Popt_dB = 10 * log10(Popt) + 30 #optical power in dbm\n", + "Popt=Popt*10**12 \n", + "print \"Minimum incident optical power is %.1f W or %.1f dBm.\" %(Popt,Popt_dB) " + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The quantum limit at the receiver to maintain bit error rate 10**-9 is (20.7*h*f)/eta.\n", + "Minimum incident optical power is 20.6 W or -76.9 dBm.\n" + ] + } + ], + "prompt_number": 5 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.2.2, page 8-8" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "SN_dB=60 #signal to noise ratio\n", + "h=6.626*10**-34 #plank's constant\n", + "c=3*10**8 #speed of light\n", + "lamda=1.3*10**-6 #wavelength\n", + "eta=1 \n", + "B=6.5*10**6 #Bandwidth\n", + "SN=10**(SN_dB/10) \n", + "f=c/lamda\n", + "Popt= 2*SN*h*f*B/eta #computing optical power\n", + "Popt_dB = 10 * log10(Popt) + 30 #optical power in dbm\n", + "Popt=Popt*10**6 \n", + "print \"Incident power required to get an SNR of 60 dB at the receiver is %.4f microWatt or %.3f dBm\" %(Popt,Popt_dB)\n", + "#Calculation error in the book.They have take SN as 10**5 while calculating, which has lead to an error in final answer\n", + "#answer in the book 198.1nW and -37.71 dBm" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Incident power required to get an SNR of 60 dB at the receiver is 1.9878 microWatt or -27.016 dBm\n" + ] + } + ], + "prompt_number": 7 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.3.1, page 8-11" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "lamda=0.85*10**-6 \n", + "h=6.626*10**-34 #plank's constant\n", + "c=3*10**8 #speed of light\n", + "q=1.6*10**-19 #charge of electron\n", + "eta=65/100 #quantum efficiency\n", + "P0=300*10**-9 #optical power\n", + "Id=3.5 #dark current\n", + "B=6.5*10**6 #bandwidth\n", + "K=1.39*10**-23 #Boltzman constant\n", + "T=293 #temperature\n", + "R=5*10**3 #load resister\n", + "Ip= 10**9*eta*P0*q*lamda/(h*c) \n", + "Its=10**9*(2*q*B*(Ip+Id)) \n", + "Its=sqrt(Its) \n", + "print \"rms shot noise current is %.2f nA.\" %(Its) \n", + "It= 4*K*T*B/R \n", + "It=sqrt(It) \n", + "It=It*10**9 \n", + "print \"Thermal noise is %.2f nA.\" %(It) \n", + "#answer given in book for Thermal noise is wrong." + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "rms shot noise current is 0.53 nA.\n", + "Thermal noise is 4.60 nA.\n" + ] + } + ], + "prompt_number": 9 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.3.2, page 8-12" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "lamda=0.85*10**-6 \n", + "h=6.626*10**-34 #plank's constant\n", + "c=3*10**8 #speed of light\n", + "q=1.6*10**-19 #charge of electron\n", + "eta=65/100 #quantum efficiency\n", + "P0=300*10**-9 #optical power\n", + "Id=3.5 #dark current\n", + "B=6.5*10**6 #bandwidth\n", + "K=1.39*10**-23 #Boltzman constant\n", + "T=293 #temperature\n", + "R=5*10**3 #load resister\n", + "F_dB=3 #noise figure\n", + "F=10**(F_dB/10) \n", + "Ip=10**9*eta*P0*q*lamda/(h*c) \n", + "Its=10**9*(2*q*B*(Ip+Id)) \n", + "It1= 4*K*T*B*F/R \n", + "SN= Ip**2/(Its+It1) \n", + "SN_dB=10*log10(SN) \n", + "SN=SN\n", + "print \"SNR is %.2e or %.2f dB.\" %(SN,SN_dB) \n", + "#answer given in the book is wrong." + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "SNR is 6.25e+04 or 47.96 dB.\n" + ] + } + ], + "prompt_number": 13 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.4.1, page 8-14" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "Cd=7*10**-12 \n", + "B=9*10**6 \n", + "Ca=7*10**-12 \n", + "R=(2*3.14*Cd*B)**-1 \n", + "B1=(2*3.14*R*(Cd+Ca))**-1 \n", + "R=R/1000 \n", + "B1=B1/10**6 \n", + "print \"\"\"Thus for 9MHz bandwidth maximum load resistance is %.2f Kohm\n", + "Now if we consider input capacitance of following amplifier Ca then Bandwidth is %.2fMHz\n", + "Maximum post detection bandwidth is half.\"\"\"%(R,B1) \n", + "#answer for resistance in the book is wrong" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Thus for 9MHz bandwidth maximum load resistance is 2.53 Kohm\n", + "Now if we consider input capacitance of following amplifier Ca then Bandwidth is 4.50MHz\n", + "Maximum post detection bandwidth is half.\n" + ] + } + ], + "prompt_number": 14 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Question 7, page 8.44" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "w=25*10**-6 #width\n", + "v=3*10**4 #velocity\n", + "t=w/v #computing drift time\n", + "BW=(2*pi*t)**-1 #computing bandwidth\n", + "rt=1/BW #response time\n", + "rt=rt*10**9 \n", + "print \"Maximum response time is %.2f ns.\" %(rt) \n", + "#Answer in the book is wrong." + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Maximum response time is 5.24 ns.\n" + ] + } + ], + "prompt_number": 16 + } + ], + "metadata": {} + } + ] +}
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