{ "metadata": { "name": "", "signature": "sha256:a49a8ec12fc3b73c3ede4bd700b2981c396abe3970143184cc460eca3744fac1" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "CHAPTER04:ANGLE MODULATION" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E03 : Pg 4.9" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.9\n", "# Example 4.3\n", "# Given\n", "fc=1.*10.**6.; # Hz\n", "kf=5.;\n", "mt=1.*10.**5.; # Hz\n", "\n", "# (a) mi(t) with fm\n", "mi=(fc+(kf*mt));\n", "print\"Max, Inst. Frequency with FM\",mi,\"Hz\"\n", "import math \n", "kp=3.;\n", "# (b) mi2(t) with pm\n", "mi2=fc+(mt*(kp/(2*math.pi)));\n", "\n", "print\"Max, Inst. Frequency with PM\",mi2,\"Hz\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Max, Inst. Frequency with FM 1500000.0 Hz\n", "Max, Inst. Frequency with PM 1047746.48293 Hz\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E09 : Pg 4.13" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.13\n", "# Example 4.9\n", "# Given\n", "delf=20.*10.**3.; # hz\n", "fm=10.*10.**3.; # Hz\n", "\n", "B=delf/fm;\n", "print\"Beta: \",B" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Beta: 2.0\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E13 : Pg 4.16" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.16\n", "# Example 4.13\n", "# Given\n", "# x(t)=10cos((2*pi*10**8*t)+(200cos(2*pi*10**3*t)))\n", "# on differentiating\n", "# wi=2*pi*(1D+8)-4*pi*sin(2*pi*(1D+3)*t)\n", "# Therefore\n", "import math \n", "delw=4.*math.pi*(1.*10.**5.);\n", "wm=2.*math.pi*(1.*10.**3.);\n", "B=delw/wm;\n", "wb=2.*(B+1.)*wm;\n", "fb=wb/2.*math.pi;\n", "print\"Wb\",wb,\"rad/s\"\n", "print\"Fb\",fb,\"Hz\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Wb 2525840.49349 rad/s\n", "Fb 3967580.96924 Hz\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E14 : Pg 4.17" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.17\n", "# Example 4.14\n", "# Given\n", "delf=100.*10.**3; # Hz\n", "fc=20.*10.**6.; # Hz\n", "\n", "# As B=delf/fm;\n", "# (a) fm1=1*10.**3hz\n", "print'Part a'\n", "fm1=1.*10.**3.; # Hz\n", "B1=delf/fm1;\n", "print'Modulation Index',B1\n", "fb1=2.*delf;\n", "print'Bandwidth',fb1,'Hz'\n", "# (b) fm2=100*10.**3hz\n", "print'\\nPart b'\n", "fm2=100.*10.**3.; # Hz\n", "B2=delf/fm2;\n", "print'Modulation Index',B2\n", "fb2=2.*(B2+1.)*fm2;\n", "print'Bandwidth',fb2,'Hz'\n", "# (c) fm3=500*10.**3hz\n", "print'\\nPart c'\n", "fm3=500.*10.**3.; # Hz\n", "B3=delf/fm3;\n", "print'Modulation Index',B3\n", "fb3=2.*fm3;\n", "print'Bandwidth',fb3,'Hz'" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Part a\n", "Modulation Index 100.0\n", "Bandwidth 200000.0 Hz\n", "\n", "Part b\n", "Modulation Index 1.0\n", "Bandwidth 400000.0 Hz\n", "\n", "Part c\n", "Modulation Index 0.2\n", "Bandwidth 1000000.0 Hz\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E15 : Pg 4.17" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.17\n", "# Example 4.15\n", "# Given\n", "# x(t)=10cos(wct+3sinwmt)\n", "# Comparing with standard equation\n", "B=3.;\n", "fm=1.*10.**3.; # hz\n", "fb=2.*(B+1.)*fm;\n", "\n", "# (a)fm is doubled\n", "fma=2.*fm;\n", "fba=2.*(B+1.)*fma;\n", "print\"fb with 2fm: \",fba\n", "\n", "# (b)fm is one halved\n", "fmb=fm/2.;\n", "fbb=2.*(B+1.)*fmb;\n", "print\"fb with 0.5fm: \",fbb" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "fb with 2fm: 16000.0\n", "fb with 0.5fm: 4000.0\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E16 : Pg 4.18" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.18\n", "# Example 4.16\n", "# Given\n", "# x(t)=10cos(wct+3sinwmt)\n", "# Comparing with standard equation of fm\n", "B=3.;\n", "fm=1.*10.**3.; # hz\n", "fb=2.*(B+1.)*fm;\n", "\n", "# B is inversaly proportional to fm\n", "\n", "# (a)fm is doubled\n", "Ba=B/2.;\n", "fma=2.*fm;\n", "fba=2.*(Ba+1.)*fma;\n", "print\"fb with 2fm: \",fba\n", "\n", "\n", "\n", "# (b)fm is one halved\n", "Bb=2.*B;\n", "fmb=fm/2.;\n", "fbb=2.*(Bb+1.)*fmb;\n", "print\"fb with 0.5fm: \",fbb" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "fb with 2fm: 10000.0\n", "fb with 0.5fm: 7000.0\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E17 : Pg 4.18" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.18\n", "# Example 4.17\n", "\n", "# Given\n", "fm=2.*10.**3.; # Hz\n", "delf=5.*10.**3.; # Hz\n", "\n", "# (a) Bandwidth of modulated signal\n", "B=delf/fm;\n", "\n", "fb=2.*(B+1.)*fm;\n", "print'Bandwidth',fb,'Hz'\n", "\n", "# (b)Max. frequency deviation and Bandwidth of new signal\n", "# Given\n", "fm1=fm-(1.*10.**3.);\n", "delf1=3.*delf;\n", "\n", "B1=delf1/fm1;\n", "\n", "fd=B1*fm1;\n", "print'Maximum frequency deviation',fd,'Hz'\n", "\n", "fb1=2.*(B1+1.)*fm1;\n", "print'Bandwidth',fb1,'Hz'" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Bandwidth 14000.0 Hz\n", "Maximum frequency deviation 15000.0 Hz\n", "Bandwidth 32000.0 Hz\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E18 : Pg 4.19" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.19\n", "# Example 4.18\n", "# Given\n", "delf=75.*10.**3.; # Hz\n", "fM=15.*10.**3.; # Hz\n", "\n", "D=delf/fM;\n", "# Given formula fb=2(*10.**2)*fM\n", "fb1=2.*10.**2.*fM;\n", "print'BW uing formula',fb1,'Hz'\n", "\n", "# Carsons Rule\n", "fb2=2.*10.**1.*fM;\n", "print'BW uing Carsons Rule',fb2,'Hz'\n", "\n", "# High quality Fm radios require minimum 200kHz\n", "# Therefore, carsons rule underestimates bandwidth" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "BW uing formula 3000000.0 Hz\n", "BW uing Carsons Rule 300000.0 Hz\n" ] } ], "prompt_number": 9 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E19 : Pg 4.19" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.19\n", "# Example 4.19\n", "# Given\n", "fm1=50.; # Hz\n", "fm2=15.*10.**3.; # Hz\n", "\n", "delf=75.*10.**3.; # Hz\n", "\n", "# As B=delf/fm\n", "Bmin=delf/fm2;\n", "Bmax=delf/fm1;\n", "\n", "# Let B1=0.5\n", "B1=0.5;\n", "n=(Bmax/B1);\n", "print'Multiplication factor',n\n", "\n", "delf1=(delf/n);\n", "print'Max allowed frequency deviation',delf1,'Hz'" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Multiplication factor 3000.0\n", "Max allowed frequency deviation 25.0 Hz\n" ] } ], "prompt_number": 10 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E20 : Pg 4.20" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.20\n", "# Example 4.20\n", "# Given\n", "f1=2.*10.**5.; # Hz\n", "fLO=10.8*10.**6.; # Hz\n", "delf1=25.; # Hz\n", "n1=64.;\n", "n2=48.;\n", "\n", "delf=(delf1*n1*n2);\n", "print'Maximum frequency deviation',delf,'Hz'\n", "\n", "f2=n1*f1;\n", "\n", "f3a=f2+fLO;\n", "f3b=f2-fLO;\n", "\n", "# For f3a\n", "fca=n2*f3a;\n", "print'Carrier frequency 1',fca,'Hz'\n", "\n", "# For f3b\n", "fcb=n2*f3b;\n", "print'Carrier frequency 2',fcb,'Hz'" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Maximum frequency deviation 76800.0 Hz\n", "Carrier frequency 1 1132800000.0 Hz\n", "Carrier frequency 2 96000000.0 Hz\n" ] } ], "prompt_number": 11 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E21 : Pg 4.20" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.20\n", "# Example 4.21\n", "# Given\n", "delf=20.*10.**3.; # Hz\n", "fc=200.*10.**3.; # Hz\n", "of=96.*10.**6.; # hz\n", "# delf=n1*n2 and as only doublers are used, n1*n2 has to be power of 2\n", "# By trail and error, we find\n", "n1=64.;\n", "n2=32.;\n", "# Output of first Multiplier\n", "o1=n1*fc;\n", "print'Output of first multiplier: ',o1,'Hz'\n", "i2=of/n2;\n", "flo=o1-i2;\n", "print'fLO',flo,'Hz'" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Output of first multiplier: 12800000.0 Hz\n", "fLO 9800000.0 Hz\n" ] } ], "prompt_number": 12 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E22 : Pg 4.20" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.20\n", "# Example 4.22\n", "# Given\n", "B=0.2; \n", "f1=200.*10.**3.; # Hz\n", "fml=50.; # Hz\n", "fmh=15.*10.**3.; # Hz\n", "delf=75.*10.**3.; # hz\n", "fc=108.*10.**6.; # Hz\n", "\n", "delf1=B*fml;\n", "n1n2=delf/delf1;\n", "\n", "# Let n2=150\n", "n2=150.;\n", "flo=((delf*f1)-fc)/n2;\n", "print'fLO',flo,'Hz'\n", "\n", "n1=n1n2/n2;\n", "print\"n1 with n2=150:\",n1" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "fLO 99280000.0 Hz\n", "n1 with n2=150: 50.0\n" ] } ], "prompt_number": 13 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E23 : Pg 4.21" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.21\n", "# Example 4.23\n", "# Given,\n", "\n", "delfd1=50.; # Hz\n", "f1=120.; # Hz\n", "\n", "delfd2=20000.; # Hz\n", "f2=240.; # Hz\n", "# (a)PM\n", "delf1=(f2/f1)*delfd1;\n", "n1=delfd2/delf1;\n", "print'Frequency multiplication factor in PM',n1\n", "\n", "# (b)FM\n", "n2=delfd2/delfd1;\n", "print'Frequency multiplication factor in FM',n2" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Frequency multiplication factor in PM 200.0\n", "Frequency multiplication factor in FM 400.0\n" ] } ], "prompt_number": 14 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E29 : Pg 4.25" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Page Number: 4.25\n", "# Example 4.29\n", "# Given,\n", "f1=108.; # MHz\n", "f2=157.; # MHz\n", "\n", "# (a) Image frequency overlaps RF band\n", "fIF=12.; # MHz\n", "\n", "fL01=f1-fIF;\n", "print'fL01',fL01,'MHz'\n", "fim1=fL01-fIF;\n", "print'fim1',fim1,'MHz'\n", "\n", "fL02=f2-fIF;\n", "print'fL02',fL02,'MHz'\n", "fim2=fL02-fIF;\n", "print'fim2',fim2,'MHz'\n", "\n", "# Clearly image and RF band overlap" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "fL01 96.0 MHz\n", "fim1 84.0 MHz\n", "fL02 145.0 MHz\n", "fim2 133.0 MHz\n" ] } ], "prompt_number": 15 } ], "metadata": {} } ] }