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{
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"name": "",
"signature": "sha256:4b08bbb242b14bb2e9d6b297d6c2efe9724a5525d0e315485c89f280e01ac4b8"
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"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 16: Direct Broadcast Satellite Services"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 16.1, Page 474"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#Varaible Declaration\n",
"\n",
"EIRP=55 #EIRP for satellite(dBW)\n",
"fD=12.5 #Downlink frequency(GHz)\n",
"Pss=-101 #Receiving at ground station direction(degrees west)\n",
"Rb=40*10**6 #Transmission Rate(Hz)\n",
"D=18 #Diameter of antenna(inches)\n",
"n=0.55 #Efficiency of antenna\n",
"Tant=70 #Antenna noise(Kelvin)\n",
"Teq=100 #Equivalent noise temperature at LNA(Kelvin)\n",
"R=6371 #Radius of earth(Km)\n",
"L=2 #Transmission losses(dB)\n",
"aGSO=42164 #Circumference of earth(km)\n",
"k=-228.6 #Boltzmann's constant (dB)\n",
"PE=-90 #Longitude of Earth station(degrees west)\n",
"LE=45 #Latitude of Earth station(degrees north)\n",
"f=14 #Frequency(GHz)\n",
"#Calculation\n",
"B=PE-Pss\n",
"b=math.acos(math.cos(B*3.142/180)*math.cos(LE*3.142/180))\n",
"b=b*180/3.142\n",
"A=math.asin(math.sin(abs(B)*3.142/180)/math.sin(b*3.142/180))\n",
"A=A*180/3.142\n",
"Az=180+A #Azimuth angle of antenna(degrees)\n",
"d=(R**2+aGSO**2-2*R*aGSO*math.cos(b*3.142/180))**0.5 #Range of antenna(km)\n",
"El=math.acos(aGSO*math.sin(b*3.142/180)/d) #Elevation angle of antenna(radians)\n",
"El=El*180/3.142 #Elevation angle of antenna(degrees)\n",
"Az=round(Az,1)\n",
"El=round(El)\n",
"d=round(d)\n",
"FSL=32.4+20*math.log10(d)+20*math.log10(f*10**3) #Free space loss(dB)\n",
"LOSSES=FSL+L #Total Transmission Losses\n",
"Ts=Teq+Tant #Total system noise temperature(Kelvin)\n",
"T=10*math.log10(Ts) #Total system noise temperature(dBK)\n",
"G=n*(3.192*f*(D/float(12)))**2\n",
"G=10*math.log10(G) #Antenna Gain(dB)\n",
"GTR=G-T #G/T ratio(dB)\n",
"CNR=EIRP+GTR-LOSSES-k #Carrier to noise ratio(dB)\n",
"Rb=10*math.log10(Rb) #Transmission Rate(dBHz)\n",
"EbN0R=CNR-Rb #Eb/N0 ratio at IRD(dB)\n",
"EbN0R=round(EbN0R,1)\n",
"#Results\n",
"\n",
"print \"The Azimuth angle of antenna is\",Az,\"degrees\"\n",
"print \"The Elevaation Angle of Antenna is\",El,\"degrees\"\n",
"print \"The Range of Antenna is\",d,\"km\"\n",
"print \"The Eb/N0 ratio at IRD is\",EbN0R,\"dB\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The Azimuth angle of antenna is 195.4 degrees\n",
"The Elevaation Angle of Antenna is 37.0 degrees\n",
"The Range of Antenna is 38020.0 km\n",
"The Eb/N0 ratio at IRD is 10.3 dB\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 16.2, Page 480"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#Varaible Declaration\n",
"\n",
"R01=42 #Rainfall at earth station(mm/hr)\n",
"p=0.01 #Percentage of time for which rain exceeds\n",
"LE=45 #Latitue of earth station(degrees)\n",
"hR=3.5 #Rain Height(km)\n",
"h0=0 #Mean Sea level(km)\n",
"Ta=272 #\n",
"El=37 #Elevation angle of the antenna(degrees)\n",
"Ts=170 #Total system noise temperature(Kelvin)\n",
"NCR=2.3*10**-9 #Carrier to noise ratio\n",
"fD=12.5 #Frequency of operation(GHz)\n",
"f12=12 #Frequency 12GHz(GHz)\n",
"f15=15 #Frequency 15GHz(GHz)\n",
"#Coefficients for horizontal and vertical polarizations at 12GHz and 15GHz as given in Table 4.2\n",
"\n",
"ah12=0.0188\n",
"av12=0.0168\n",
"bh12=1.217\n",
"bv12=1.2\n",
" \n",
"ah15=0.0367\n",
"av15=0.0335\n",
"bh15=1.154\n",
"bv15=1.128\n",
"\n",
"#Calculation\n",
"\n",
"#Using Interpolation to find coefficients at 12.5 GHz\n",
"\n",
"ah=round(ah12+(ah15-ah12)*(fD-f12)/(f15-f12),3)\n",
"bh=round(bh12+(bh15-bh12)*(fD-f12)/(f15-f12),3)\n",
"av=round(av12+(av15-av12)*(fD-f12)/(f15-f12),3)\n",
"bv=round(bv12+(bv15-bv12)*(fD-f12)/(f15-f12),3)\n",
"\n",
"#Coefficients for circular polarization\n",
"\n",
"ac=(ah+av)/2\n",
"ac=round(ac,3)\n",
"bc=(ah*bh+av*bv)/(2*ac)\n",
"bc=round(bc,3)\n",
"Ls1=(hR-h0)/math.sin(El*3.142/180) #Slant Path Length(km)\n",
"Ls=round(Ls1,1) #Slant Path Length(km)\n",
"LG=round(Ls*math.cos(El*3.142/180),1) #Horizontal projection of slant path length(km)\n",
"r011=90/(90+4*LG) #Reduction Factor\n",
"r01=round(r011,1) #Reduction Factor\n",
"L=round(Ls1*r01,1) #Effective path length(km)\n",
"alpha=round(ac*R01**bc,3) #Specific attenuation(dB/km)\n",
"A=round(10**(alpha*L/float(10)),1) #Total Attenuation(dB)\n",
"Trn=Ta*(1-1/A) #noise temperature with effect of rain\n",
"Tscs=Ts\n",
"NCrain=NCR*(A+(A-1)*Ta/Tscs) #Noise to carrier ratio due to rain\n",
"CNrain=-10*math.log10(NCrain)#Noise to carrier ratio due to rain(dB)\n",
"Rb=10*math.log10(40*10**6) #Transmission rate(dB)\n",
"EbN0rain=round(CNrain-Rb,1) #Upper limit of Eb/N0 ratio in prescence of rain(dB)\n",
"\n",
"#Result\n",
"\n",
"print \"Hence the upper limit for Eb/N0 for given conditions is\",EbN0rain,\"dB\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Hence the upper limit for Eb/N0 for given conditions is -2.1 dB\n"
]
}
],
"prompt_number": 2
}
],
"metadata": {}
}
]
}
|
