{ "metadata": { "name": "Chapter 10" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 10: Microwave Communication Systems" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.1, Page number 486" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "from math import sqrt\n", "\n", "#Variable declaration\n", "ht = 144 #transmitter antenna height(m)\n", "hr = 25 #receiving antenna height(M)\n", "\n", "#Calculations\n", "dt = 4*sqrt(ht)\n", "dr = 4*sqrt(hr)\n", "d = dt+dr\n", "\n", "#Results\n", "print \"Radio horizon is\",dt,\"km\"\n", "print \"The maximum distance of propagation of the TV signal is\",d,\"km\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Radio horizon is 48.0 km\n", "The maximum distance of propagation of the TV signal is 68.0 km\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.2, Page number 486" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "from fractions import Fraction\n", "\n", "#Variable declaration\n", "r = 6370*10**3 #radius of earth(km)\n", "du_dh = -0.05*10**-6 #refractive index of air near ground\n", "\n", "#Calculations\n", "k = 1/(1+(r*du_dh))\n", "\n", "#Result\n", "print \"The horizon distance of the transmitter can be modified by replaing r by r' is\",round(k,3),\"r\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The horizon distance of the transmitter can be modified by replaing r by r' is 1.467 r\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.3, Page number 487" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import math \n", "#Variable declaration\n", "c = 3.*10**8 #velocity of propagation(m/s)\n", "f = 2*10**9 #frequency(Hz)\n", "r = 50*10**3 #repeater spacing(km)\n", "Pr = 20 #carrier power(dBm)\n", "Gt = 34 #antenna gain(dB)\n", "L = 10 #dB\n", "Gr = 34 #dB\n", "\n", "#Calculations\n", "lamda = c/f\n", "Pt = -Pr+(10*math.log10(4*math.pi*r**2))-Gt-(10*math.log10(lamda**2/(4*math.pi)))+L-Gr\n", "\n", "#Results\n", "print \"The carrier tansmitted power required is\",round(Pt,2),\"dBm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The carrier tansmitted power required is 54.44 dBm\n" ] } ], "prompt_number": 25 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Exampl 10.4, Page number 487" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import math\n", "\n", "#Variable declaration\n", "f = 6.*10**9 #uplink frequency(Hz)\n", "e = 5 #elevation angle(degrees)\n", "Pt = 1.*10**3 #transmitter power(W)\n", "Gt = 60. #gain of transmitter(dB)\n", "Gr = 0 #gain of receiver(dB)\n", "d = 36000*10**3 #distance between ground and satellite(m)\n", "c = 3.*10**8 #velocity of propagation(m/s)\n", "\n", "#Calculation\n", "Gt1 = 10**(Gt/10)\n", "Gr1 = 10.**(Gr/10)\n", "r = d/(math.sin(math.radians(e)))\n", "lamda = c/f\n", "Pr = (Pt*Gt1*Gr1*lamda**2)/(4*math.pi*r**2*4*math.pi)\n", "\n", "#Result\n", "print \"Received power =\",round((Pr/1E-14),1),\"*10^-14 W\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Received power = 9.3 *10^-14 W\n" ] } ], "prompt_number": 41 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.5, Page number 487" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import math\n", "\n", "#Variable declaration\n", "r = 6371 #radius of the earth(km)\n", "\n", "#Calculation\n", "d = 35855+r #distance of satellite from center of the earth(km)\n", "b = (math.degrees(math.pi)*r)/d\n", "\n", "#Result\n", "print \"Antenna beam angle =\",round(b,2),\"degrees\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Antenna beam angle = 27.16 degrees\n" ] } ], "prompt_number": 47 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.6, Page number 488" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import math\n", "\n", "#Variable declaration\n", "r = 6371 #radius of earth(km)\n", "h = 35855 #height(km) \n", "phi = 5 #elevation angle(degrees)\n", "c = 3*10**8 #velocity of propagation(m/s)\n", "B = 90 #angle for vertical transmission(degrees)\n", "\n", "#Calculations\n", "d = math.sqrt(((r+h)**2)-((r*math.cos(math.radians(phi)))**2))- (r*math.sin(math.radians(phi)))\n", "T = (2*d*10**3)/c\n", "dv = math.sqrt(((r+h)**2)-(r**2))\n", "Tv = (2*(dv-r)*10**3)/c\n", "\n", "#Results\n", "print \"The round trip time between earth station and satellite is\",round((T/1E-3),2),\"msec\"\n", "print \"The round trip time for vertical transmission is\",round((Tv/1E-3),2),\"msec\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The round trip time between earth station and satellite is 274.61 msec\n", "The round trip time for vertical transmission is 235.81 msec\n" ] } ], "prompt_number": 53 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.7, Page number 488" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import math\n", "\n", "#Variable declaration\n", "Tant = 25 #effective noise temperature for antenna(K)\n", "Tr = 75 #receiver oise temperature(K)\n", "G = 45 #power gain(dB)\n", "\n", "#Calculations\n", "T = Tant+Tr\n", "Tdb = 10*math.log10(T)\n", "M = G - Tdb\n", "\n", "#Results\n", "print \"The figure of merit for earth station is\",M,\"dB\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The figure of merit for earth station is 25.0 dB\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.8, Page number 488" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#Variable declaration\n", "EIRP = 55.5 #satellite ESM(dBW)\n", "M = 35 #freespace loss(dB)\n", "Lfs = 245.3 #GT of earth station(dB)\n", "\n", "#Calculation\n", "C_No = EIRP + M - Lfs + 228.6\n", "\n", "#Result\n", "print \"The carrier to noise ratio is\",round(C_No,2),\"dB\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The carrier to noise ratio is 73.8 dB\n" ] } ], "prompt_number": 9 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.9, Page number 489" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import math\n", "\n", "#Variable declaration\n", "D = 30 #diameter of dish(m)\n", "f = 4*10**9 #downlink frequency(Hz)\n", "M = 20 #G/T ratio of earth station\n", "c = 3.*10**8 #velocity of propagation(m/s)\n", "\n", "#Calculations\n", "Ae = (math.pi*D**2)/4\n", "lamda = c/f\n", "G = (4*math.pi*Ae)/lamda**2\n", "Gdb = 10*math.log10(G)\n", "Ts = Gdb - M\n", "\n", "#Result\n", "print \"The system noise temperature is\",round(Ts,2),\"dB\" " ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The system noise temperature is 41.98 dB\n" ] } ], "prompt_number": 24 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.10, Page number 489" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import math\n", "\n", "#Variable declaration\n", "Gp = 1500 #power gain\n", "lamda = 10*10**-2 #m\n", "\n", "#Calculations\n", "D = math.sqrt((Gp*(lamda**2))/(math.pi**2))\n", "HPBW = 58*lamda/D\n", "\n", "#Results\n", "print \"The diamater of parabolic antenna is\",round(D,2),\"m\"\n", "print \"Half power beam width of paraboic antenna =\",round(HPBW,2)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "15791.3670417\n", "The diamater of parabolic antenna is 1.23 m\n", "Half power beam width of paraboic antenna = 4.7\n" ] } ], "prompt_number": 37 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.11, Page number 490" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "import math\n", "\n", "#Variable declaration\n", "then Gp1 = (6*D1**2)/(lamda**2)\n", "If the gain and diameter of the antenna in the modified system is Gp2 and d2,\n", "then Gp2 = (6*D2**2)/(lamda**2)\n", "Gain = 10*log(Gp2/Gp1)\n", "\n", "#Calculations\n", "G = 10*math.log10(2)\n", "Gall = 2*G\n", "\n", "#Results\n", "print \"Overall gain of the system is\",round(Gall,2),\"dB\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Overall gain of the system is 6.02 dB\n" ] } ], "prompt_number": 45 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Esample 10.12, Page number 490" ] }, { "cell_type": "code", "collapsed": false, "input": [ "a)beamwidth between first nulls\n", "b)beamwidth between half power points\n", "\n", "#Variable declaration\n", "D = 3*10**2 #diameter of paraboloid(cm)\n", "f = 3.*10**9 #frequency(Hz)\n", "c = 3.*10**10 #velocity of propagation(m/s)\n", "\n", "#Calculations\n", "lamda = c/f\n", "BWFN = (140*lamda)/D\n", "BWHP = (70*lamda)/D\n", "Gp = (6*D**2)/(lamda**2)\n", "\n", "#Results\n", "print \"Beamwidth between first nulls =\",round(BWFN,2),\"degrees\"\n", "print \"Beamwidth between half power points =\",round(BWHP,2),\"degrees\"\n", "print \"Gain of antenna =\",round(Gp,2)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Beamwidth between first nulls = 4.67 degrees\n", "Beamwidth between half power points = 2.33 degrees\n", "Gain of antenna = 5400.0\n" ] } ], "prompt_number": 51 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.13, Page number 490" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#Variable declaration\n", "A = 5\n", "\n", "#Calculation\n", "Gp = 4.5*A**2\n", "\n", "#Result\n", "print \"Power gain of optimum horn antenna =\",Gp\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Power gain of optimum horn antenna = 112.5\n" ] } ], "prompt_number": 53 } ], "metadata": {} } ] }