{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 5 Frequency Modulation : Transmission" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.1 Page no 209" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "v=25*10**-3\n", "f=750 #deviation constant\n", "vg=10.0*10**-3 #deviation constant\n", "\n", "#calculation\n", "pfd=v*(f/vg) #positive frequency deviation\n", "nfd=-v*(f/vg) #negative frequency deviation\n", "\n", "#result\n", "print\"(a) positive frequency deviation = \",pfd,\"Hz\"\n", "print\"negative frequency deviation = \",nfd,\"Hz\"\n", "print\"The total deviation is written as +-2.25kHz for the given input signal level\"\n", "print\"(b) The carrier wil deviate \",pfd,\"Hz\",\"&\",nfd,\"Hz\",\"at 400 Hz\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a) positive frequency deviation = 1875.0 Hz\n", "negative frequency deviation = -1875.0 Hz\n", "The total deviation is written as +-2.25kHz for the given input signal level\n", "(b) The carrier wil deviate 1875.0 Hz & -1875.0 Hz at 400 Hz\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.3 Page no 214" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "d=20*10**3 #maximum deviation\n", "fi=10.0*10**3 #input frequency\n", "\n", "#calculation\n", "mf=d/fi\n", "a=mf*40\n", "\n", "#result\n", "print\"total required bandwidth is \",a,\"KHz\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "total required bandwidth is 80.0 KHz\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.4 Page no 214" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "d=20*10**3 #maximum deviation\n", "fi=5.0*10**3 #input frequency\n", "\n", "#calculation\n", "mf=d/fi\n", "a=2*35\n", "\n", "#print\n", "print\"the required bandwidth is \",mf\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "the required bandwidth is 4.0\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.5 Page no 215" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "Vm=2000\n", "R=50.0 #resistance, ohm\n", "\n", "#calcultion\n", "import math\n", "fc=(2*math.pi*(10**8))/2.0*math.pi\n", "P=(2000/math.sqrt(2))**2/R\n", "mf=2 #by inspection of FM equation\n", "fi=(math.pi*10**4)/(2.0*math.pi)\n", "d=(mf*fi)\n", "BW=mf*40\n", "bw=2*(d+fi)\n", "P1=((0.58*2000/math.sqrt(2))**2)/R\n", "P2=((0.03*2000/math.sqrt(2))**2)/R\n", "\n", "#result\n", "print\"(a) carrier frequency = \",round(fc,-9),\"Hz\" #by inspection of FM equation\n", "print\"(b) the peak voltage is 2000V P thus= \",P,\"W\"\n", "print\"(c) mf = 2\" #by inspection of FM equation\n", "print\"(d) the intelligence frequency fi = \",fi,\"Hz\"\n", "print\"(e) BW = \",bw ,\"Hz\" #using carson's rule \n", "print\"(f) The smallest sideband J4 is 0.03 times the carrier = \",P2,\"W\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a) carrier frequency = 1000000000.0 Hz\n", "(b) the peak voltage is 2000V P thus= 40000.0 W\n", "(c) mf = 2\n", "(d) the intelligence frequency fi = 5000.0 Hz\n", "(e) BW = 30000.0 Hz\n", "(f) The smallest sideband J4 is 0.03 times the carrier = 36.0 W\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.6 Page no 218" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "d=75*10**3 #maximum deviation\n", "fi=30.0 #modulating frequency, Hz\n", "fi1=15.0*10**3 \n", "d1=1*10**3\n", "fi2=100 #Hz\n", "fi3=2.0*10**3\n", "\n", "#calculation\n", "mf1=d/fi\n", "mf2=d/fi1\n", "mf3=d1/fi2\n", "mf4=d1/fi3\n", "DR=d1/fi3\n", "\n", "#result\n", "print\"(a)maximum deviation at 30 Hz = \",mf1 \n", "print\"maximum deviation at 15kHz= \",mf2\n", "print\"(b) maximum deviation at 100Hz = \",mf3\n", "print\"maximum deviation at 2KHz= \",mf4\n", "print \"(c)Deviation Ratio \",DR #deviation ratio" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a)maximum deviation at 30 Hz = 2500.0\n", "maximum deviation at 15kHz= 5.0\n", "(b) maximum deviation at 100Hz = 10\n", "maximum deviation at 2KHz= 0.5\n", "(c)Deviation Ratio 0.5\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.7 Page no 218" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "mf=0.25\n", "a=0.98\n", "b=0.12\n", "x=10*10**3 #power, watt\n", "\n", "#calculation\n", "P=(a**2)*x\n", "P1=(b**2)*x\n", "t=P+2*P1\n", "\n", "#result\n", "print\"power of each sideband = \",P1,\"W\"\n", "print\"total power = \",round(t,-4),\"W\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "power of each sideband = 144.0 W\n", "total power = 10000.0 W\n" ] } ], "prompt_number": 31 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.8 Page no 222" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "phi=0.5 #maximum intelligence frequency\n", "fi=5.0*10**3\n", "x=75*10**3\n", "\n", "#calculation\n", "d=phi*fi\n", "y=x/d\n", "\n", "#result\n", "print\"o/p S/N = \",y\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "o/p S/N = 30.0\n" ] } ], "prompt_number": 34 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5.9 Page no 222" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "dm=10*10**3\n", "x=(1/3.0) #N/S input ratio\n", "\n", "#calculation\n", "import math\n", "phi=math.asin(x)\n", "phi1=math.asin(x)\n", "fi=3*10**3\n", "d=phi1*fi\n", "a=dm/d\n", "\n", "#result\n", "print\"The S/N output will be \",round(a,0)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The S/N output will be 10.0\n" ] } ], "prompt_number": 36 } ], "metadata": {} } ] }