Implementation 16 QAM Base Band Communication System
description
Transcript of Implementation 16 QAM Base Band Communication System
Implementation 16 QAM Base Band Implementation 16 QAM Base Band
Communication SystemCommunication System
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What is QAMWhat is QAM
In QAM two DSB signals are transmitted using the In QAM two DSB signals are transmitted using the carrier of the same frequency but in Phase carrier of the same frequency but in Phase
Quadrature to each other.Quadrature to each other.
2/
m1(t)
m2(t)
Cos ωc t
Sin ωc t
Φ QAM(t)
Quadrature Modulator
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MathematicallyMathematically
φ QAM(t) = m(t) cosωt + m(t) sinωt
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Demodulator Demodulator
At the demodulator side the signal is coherently At the demodulator side the signal is coherently detected using to local carriers in phase detected using to local carriers in phase Quadrature as shown belowQuadrature as shown below
2/
2 Cos ωc t
2 Sin ωc t
X1 (t)
X 2 (t)
Low Pass Filter
Low Pass Filter
m1(t)
m2(t)
Φ QAM(t)
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MathematicallyMathematically
x(t)x(t) == 22φφ cosω(t) cosω(t)
=2[m(t) cosωt + m(t) sinωt] cosωt=2[m(t) cosωt + m(t) sinωt] cosωt
= m(t)+ m(t) cos2ωt + m(t) sin2ωt= m(t)+ m(t) cos2ωt + m(t) sin2ωt
Matlab ImplementationMatlab Implementation
Part 2Part 2
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Problem SolutionProblem Solution
Random signal generationRandom signal generation
Formation of symbols Formation of symbols
16-QAM modulation16-QAM modulation
AWGN channelAWGN channel
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Problem Solution contd…Problem Solution contd…
DemodulationDemodulation
Computation of Prob. of Bit ErrorComputation of Prob. of Bit Error
Extraction of bits from the noisy symbols.Extraction of bits from the noisy symbols.
Computation of Prob. of Symbol ErrorComputation of Prob. of Symbol Error
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AnalysisAnalysis
0 5 10 15 20 25 30 35 400
0.5
1(1st 40 out of 100,000) Message Bits
Bits-->
Bit
valu
e
1 2 3 4 5 6 7 8 9 100
5
10
15(1st 10 out of 25,000)Message Symbols
Symbols-->
Mag
nitu
de
data1
1010
-5 0 5-5
-4
-3
-2
-1
0
1
2
3
4
5
Qua
drat
ure
In-Phase
Received Signal Constellation
1111
Outputs (Command Prompt)Outputs (Command Prompt)
Total number of bits transmitted = 100000Total number of bits transmitted = 100000
Total_number_of_erroneous_bits_received = 3Total_number_of_erroneous_bits_received = 3
Probability_of_bit_error = 3.0000e-005Probability_of_bit_error = 3.0000e-005
Total_number_of_erroneous_symbols_received = 3Total_number_of_erroneous_symbols_received = 3
Probability_of_symbol_error = 1.2000e-004Probability_of_symbol_error = 1.2000e-004
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ApplicationsApplications
To multiplex the chrominance signals in To multiplex the chrominance signals in color televisioncolor television
POTSPOTS
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LimitationsLimitations
Source coding can be applied.Source coding can be applied.
Channel CodingChannel Coding
Random Voice Signal as InputRandom Voice Signal as Input
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ConclusionsConclusions
Transmission Symbol Rate Transmission Symbol Rate
Channel utility.Channel utility.
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Acknowledgements Acknowledgements
First of all we are thankful to all Mighty First of all we are thankful to all Mighty Allah. Allah. We really acknowledge Dr. Riaz Inayat for We really acknowledge Dr. Riaz Inayat for the knowledge that he conveyed to us.the knowledge that he conveyed to us.In the last but never the least, we are In the last but never the least, we are grateful to Mr. Raheel Satti and Usama grateful to Mr. Raheel Satti and Usama Bajwa for the support and help they gave Bajwa for the support and help they gave us when ever we required.us when ever we required.