1. ECEN5533 Modern Commo Theory Lesson #21. 29 February 2016 Dr
ECEN5533 Modern Commo Theory Lesson # February 2016 Dr. George Scheets
Read 4.1 – 4.3
Problems 3.13 & 14; 4.1 & 2
Quiz #2 on 7 March

2. Modulation & Demodulation
-B B
f (Hz)
Baseband
fc-B fc fc+B
XMTR RF
2fc-B 2fc 2fc+B
RCVR Demod
Multiply by a sinusoid carrier at fc Hz
Multiply by a sync'd RCVR Local Oscillater sinusoid at fc Hz

4. ECEN5533 Modern Commo Theory Lesson #22. 2 March 2016 Dr
ECEN5533 Modern Commo Theory Lesson #22 2 March 2016 Dr. George Scheets
Read 4.4 – 4.5
Problems 4.4, 6, 8, & 9
Quiz #2 on 7 March

5. OSU IEEE March General Meeting 5:30-6:30 pm, Wednesday, 9 March ES201b
Reps from American Electric Power will present
Dinner will be served + 3 points extra credit
All are invited

7. Syncing to Anti-podal BPSK
Message m(t) = + & - 1volt peak pulses
x(t) = m(t)cos(2πfct)
Square x(t) to get x(t)2 = m(t)2cos2(2πfct)
Band pass filter to get double frequency term
cos(2π2fct)
Run thru hard limiter to get 2fc Hz square wave
Run thru divide by 2 counter to get fc Hz square wave
Filter out harmonics to get fc Hz cosine

9. PSK Signal Constellations
Distance along I axis is cosine Vpeak
Distance along Q axis is sine Vpeak
Distance from origin is magnitude
[Vcosine_peak2 + Vsine_peak2] 0.5
source: slideplayer.com

10. 16 QAM Signal Constellations
Distance along I axis is cosine Vpeak
Distance along Q axis is sine Vpeak
Distance from origin is magnitude
[Vcosine_peak2 + Vsine_peak2] 0.5
source: waltertech426.blogspot.com/2013/08/matlab-m-ary-quadrature-signal.html & Wikipedia

11. Direct Conversion Receiver Quadrature Detection
Q Channel
0.5αsin(0) +
n1(t)
Sample
αcosωt
Decision
sinωt
cosωt
0.5αcos(0) +
n2(t)
Sample
I Channel
Output
Log2M
bits/symbol
source:

12. 16 QAM Signal Constellations
Transmitted Constellation has dots
Received Constellation samples are random
Divide into bins
Get a histogram, in the limit get PDF
source: waltertech426.blogspot.com/2013/08/matlab-m-ary-quadrature-signal.html & Wikipedia

13. fX(x) = In Phase Noise PDF fY(y) = Quadrature Noise PDF
2nd order Gaussian PDF
fXY(x,y) = fX(x)fY(y)
fX(x) = In Phase Noise PDF
fY(y) = Quadrature Noise PDF
source:

14. 16 QAM Signal Constellations
Transmitted Constellation has dots
16 Decision Regions at RCVR
P(Symbol OK | Circled Symbol RCV'd) = P[(-0.7 < X < 0) ∩ (0 < Y < 0.7)]
source: waltertech426.blogspot.com/2013/08/matlab-m-ary-quadrature-signal.html & Wikipedia

15. P(symbol is RCV'd OK | circled symbol transmitted)
2nd order Gaussian PDF
P(symbol is RCV'd OK | circled symbol transmitted)
= ∫ ∫ fX(x)fY(y)dxdy
= ∫fX(x)dx ∫fY(y)dy
x integrated from -0.7 to 0
y integrated from 0 to +0.7
source:

16. QAM Signal Generation
αsin(ωt) + βcos(ωt) = γcos(ωt + θ) γ = [α2 + β2]0.5 θ = tan-1(-α/β)

17. 16 QAM Signal Constellation
3cos(ωt) + 1sin(ωt) 3.162cos(ωt – 18.43◦)
source: waltertech426.blogspot.com/2013/08/matlab-m-ary-quadrature-signal.html & Wikipedia

18. Direct Conversion Receiver Quadrature Detection
-1.581sin(-18.43◦) =
Q Channel
Sample
Decision
sinωt
cosωt
1.581cos(-18.43◦)
= 1.50
Sample
3.162cos(ωt – 18.43◦)
I Channel
AGC
Required!
source:

19. 16 QAM Signal Constellation.
1.5cos(ωt) + 0.5sin(ωt)
Above is expected RCVR constellation? Closer to wrong symbol → Symbol Error
source: waltertech426.blogspot.com/2013/08/matlab-m-ary-quadrature-signal.html & Wikipedia

21. ECEN5533 Modern Commo Theory Lesson #23. 4 March 2016 Dr
ECEN5533 Modern Commo Theory Lesson #23 4 March 2016 Dr. George Scheets
Problems: Old Quiz #2
Chapters 2-5
Quiz #2 on 7 March
Reworked Design #1 due 11 March
Extra Credit Points are still unclaimed

22. OSU IEEE March General Meeting 5:30-6:30 pm, Wednesday, 9 March ES201b
Reps from American Electric Power will present
Dinner will be served + 3 points extra credit
All are invited

23. Matched Filter Detection
Finished comparing coherent binary ASK vs. PSK vs. FSK for memoryless Gaussian Noise channel Antipodal PSK has best P(Bit Error)
Bandwidth Required?
ASK & PSK require same amount: 2R Hz
FSK a bit more: 2.75R Hz for best P(BE)