{ "metadata": { "name": "", "signature": "sha256:c4970c321276b9f7170413d941bf292098cec215a7f4a0308f53e52cf40aad5c" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 9: Transmission Lines" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.1, page no. 237" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "# Variable Declaration\n", "Zo = 75 # Characteristic Impedance (Ohms) \n", "C = 69.00*pow(10,-12) # Nominal Capacitance (F/m)\n", "Di = 0.584*pow(10,-3) # Inner core diameter (m)\n", "k = 2.23 # Dielectric Constant\n", "\n", "# Calculation\n", "import math # Math Library\n", "L = pow(Zo,2)*C # Inductance per meter (H/m)\n", "Do = Di*pow(10,Zo*math.sqrt(k)/138) # Outer core diameter (m)\n", "\n", "# Result\n", "print \"Inductance per meter, L =\",round(L/pow(10,-6),3),\"uH/m\"\n", "print \"Outer Diameter, D =\",round(Do/pow(10,-3),2),\"mm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Inductance per meter, L = 0.388 uH/m\n", "Outer Diameter, D = 3.78 mm\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.2, page no. 237" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "# Variable Declaration\n", "s = 1 # Assumed s (m)\n", "d = s # Condition for minimum Zo (m)\n", "\n", "# Calculation\n", "import math # Math Library\n", "Zo_min = 276*math.log10(2*s/d) # Minimum value of characteristic impedance (Ohms)\n", " \n", "# Result\n", "print \"The minimum value of characteristic impedance, Zo_min =\",round(Zo_min),\"Ohms\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The minimum value of characteristic impedance, Zo_min = 83.0 Ohms\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.3, page no. 237" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "# Variable Declaration\n", "Zo = 2000 # Characteristic Impedance (Ohms) \n", "Di = 0.025*pow(10,-3) # Inner cable diameter (m)\n", "k = 2.56 # Dielectric Constant \n", "\n", "# Calculation\n", "import math # Math Library\n", "Do = Di*pow(10,Zo*math.sqrt(k)/138) # Outer conductor diameter (m)\n", "\n", "# Result\n", "print \"Outer Diameter, D =\",round(Do/pow(10,18),2),\"* 10^(15) km or\",round(Do/(9.44*pow(10,15))),\"light years\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Outer Diameter, D = 3.86 * 10^(15) km or 409.0 light years\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.4, page no. 243" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "# Variable Declaration\n", "Zo = 200 # Characteristic Impedance of main line (Ohms) \n", "Zl = 300 # Load Impedance (Ohms)\n", "\n", "# Calculation\n", "import math # Math Library\n", "Zo1 = math.sqrt(Zo*Zl) # Characteristic impedance of the quarter wave transformer (Ohms)\n", "\n", "# Result\n", "print \"Characteristic impedance of the quarter wave transformer, Zo1 =\",round(Zo1),\"Ohms\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Characteristic impedance of the quarter wave transformer, Zo1 = 245.0 Ohms\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.5, page no. 246" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "# Variable Declaration\n", "Zl = complex(200,75) # Load Impedance (Ohms)\n", "Zo = 300 # Characteristic Impedance (Ohms)\n", "\n", "# Calculation\n", "import math # Math Library\n", "Yl = 1/Zl # Admittance (Mho)\n", "Bstub = 1/Yl.imag # Reactance of the Stub (Ohms)\n", "Gl = Yl.real # Real Part of Admittance (Mho)\n", "Rl = 1/Gl # Resistance (Ohms)\n", "Zo1 = math.sqrt(Zo*Rl) # Characteristic impedance of the quarter wave transformer (Ohms)\n", "\n", "# Result\n", "print \"Reactance of the stub, Bstub =\",round(Bstub,1),\"Ohms\"\n", "print \"Characteristic impedance of the quarter wave transformer, Zo1 =\",round(Zo1),\"Ohms\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Reactance of the stub, Bstub = -608.3 Ohms\n", "Characteristic impedance of the quarter wave transformer, Zo1 = 262.0 Ohms\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.6, page no. 250" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "# Variable Declaration\n", "Y = complex(0.004,0.002) # Load Susceptance (Ohms)\n", "Yo = 0.0033 # Ohms - Characteristic Admittance (Ohms)\n", "f = 150*pow(10,6) # Operating Frequency (Hz)\n", "vc = 3*pow(10,8) # Speed of light in vacuum (m/s)\n", "\n", "# Calculation\n", "import math # Math Library\n", "y = Y/Yo # Normalized susceptance required to cancel loads normalized susceptance\n", "Lambda = vc/f # Wavelength (m)\n", "Length = 0.337*Lambda # Length from Smith Chart (m)\n", "\n", "# Result\n", "print \"Normalized susceptance required to cancel loads normalized susceptance = +j *\",round(y.imag,2)\n", "print \"Length =\",round(Length*100,1),\"cm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Normalized susceptance required to cancel loads normalized susceptance = +j * 0.61\n", "Length = 67.4 cm\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.7, page no. 250" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "# Variable Declaration\n", "Z = complex(100,50) # Load Impedance (Ohms)\n", "Zo = 75 # Characteristic Impedance (Ohms)\n", "\n", "# Calculation\n", "import math # Math Library\n", "z = Z/Zo # Normalized Load Impedance (Ohms)\n", "Zg = 39.8 # Resistance at Distance = 0.184* Lambda, from Smith Chart (Ohms)\n", "Zo_dash = math.sqrt(Zg*Zo) # Impedance of the transformer (Ohms)\n", "\n", "# Result\n", "print \"(a) From Smith Chart the Distance = 0.184 * Lambda\"\n", "print \"(b) Zo_dash for the transformer, Zo' =\",round(Zo_dash,1),\"Ohms\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a) From Smith Chart the Distance = 0.184 * Lambda\n", "(b) Zo_dash for the transformer, Zo' = 54.6 Ohms\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.8, page no. 253" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "# Variable Declaration\n", "Z = complex(450,-600) # Load Impedance (Ohms)\n", "Zo = 300 # Characteristic Impedance (Ohms)\n", "\n", "# Calculation\n", "import math # Math Library\n", "z = Z/Zo # Normalized Load Impedance (Ohms)\n", "s = 4.6 # Standing Wave Ratio\n", "L = 1/(2*math.pi)*math.atan(math.sqrt(s)/(s-1)) # (* Lambda) Stub Length (m)\n", "\n", "# Result\n", "print \"Normalized load Impedance = \",z\n", "print \"From Smith Chart the Distance to the stub = 0.130 * Lambda\"\n", "print \"Stub Length =\",round(L,3),\"* Lambda\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Normalized load Impedance = (1.5-2j)\n", "From Smith Chart the Distance to the stub = 0.130 * Lambda\n", "Stub Length = 0.086 * Lambda\n" ] } ], "prompt_number": 9 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.9, page no. 254" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "# Variable Declaration\n", "Z = complex(450,-600) # Load Impedance (Ohms)\n", "Zo = 300 # Characteristic Impedance (Ohms)\n", "f1 = 10 # Old frequency (MHz)\n", "f2 = 12 # New frequency (MHz)\n", "\n", "# Calculation\n", "import math # Math Library\n", "z = Z/Zo # Normalized Load Impedance (Ohms)\n", "z1 = z.imag * f1/f2 # Intermediate Impedance (Ohms)\n", "z = complex(z.real,z1) # Normalized Load Impedance (Ohms)\n", "s = 4.6 # Standing Wave Ratio\n", "L = 1/(2*math.pi)*math.atan(math.sqrt(s)/(s-1))*f2/f1 # (* Lambda')Stub Length (m)\n", "\n", "# Result\n", "print \"Normalized load Impedance = \",z\n", "print \"From Smith Chart the Distance to the stub = 0.156 * Lambda'\"\n", "print \"Stub Length =\",round(L,3),\"* Lambda'\"\n", "print \"From Smith chart SWR = 2.2\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Normalized load Impedance = (1.5-1.66666666667j)\n", "From Smith Chart the Distance to the stub = 0.156 * Lambda'\n", "Stub Length = 0.103 * Lambda'\n", "From Smith chart SWR = 2.2\n" ] } ], "prompt_number": 10 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.10, page no. 256" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "# Variable Declaration\n", "Z = 200.00 # Load Impedance (Ohms)\n", "Zo = 300.00 # Characteristic Impedance (Ohms)\n", "\n", "# Calculation\n", "import math # Math Library\n", "z = Z/Zo # Normalized Load Impedance (Ohms)\n", "L1_by_Lambda = 0.311 # Ratio from Smith Chart\n", "L2_by_Lambda1 = L1_by_Lambda*1.1 # Ratio\n", "\n", "# Result\n", "print \"(a) Normalized load Impedance = \",round(z,2)\n", "print \" From Smith Chart the Distance to the stub = 0.11 * Lambda\"\n", "print \" From Smith Chart the Length of stub = 0.311 * Lambda\"\n", "print \"(b) New Length of stub =\",round(L2_by_Lambda1,3),\"* Lambda'\"\n", "print \" From Smith chart SWR = 1.3\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a) Normalized load Impedance = 0.67\n", " From Smith Chart the Distance to the stub = 0.11 * Lambda\n", " From Smith Chart the Length of stub = 0.311 * Lambda\n", "(b) New Length of stub = 0.342 * Lambda'\n", " From Smith chart SWR = 1.3\n" ] } ], "prompt_number": 11 } ], "metadata": {} } ] }