1. ECEN5533. Modern Communications Theory Lecture #4. 20 January 2015 Dr
ECEN Modern Communications Theory Lecture #4 20 January 2015 Dr. George Scheets
Review Appendix A Problems: Quiz #1,
Quiz #1, 27 January
Chapter 1 (Review)
Open Book & Notes

2. ECEN5533. Modern Communications Theory Lecture #5. 22 January 2015 Dr
ECEN Modern Communications Theory Lecture #5 22 January 2015 Dr. George Scheets
Read 5.1 – 5.3 Problems: Quiz #1,
Quiz #1, 27 January
Chapter 1 (Review)
Open Book & Notes

3. Last Week Time Average Autocorrelation
Common Notation: A[x(t)x(t+τ)] or <x(t)x(t+τ)>
Easier to use & understand than Statistical Autocorrelation E[X(t)X(t+τ)]
Fourier Transform yields GX(f)
Autocorrelation of a Random Binary Square Wave
Triangle, possibly riding on a constant term
Fourier Transform is sinc2 & delta function at f = 0 Hz
Linear Time Invariant Systems
If LTI, H(f) exists & GY(f) = GX(f)|H(f)|2

4. Directional Antennas

5. RF Antenna Directivity
Maximum Power Intensity Average Power Intensity
WARNING! Antenna Directivity is NOT = Antenna Power Gain 10w in? Max of 10w radiated.
Treat Antenna Power Gain = 1
Antenna Gain = Power Gain * Directivity
High Gain = Narrow Beam

6. Parabolic Directivity
source: en.wikipedia.org/wiki/Parabolic_antenna

7. Some Common Link Equation Terms
EIRP = PtGt
Path Loss Ls = (4*π*d/λ)2

8. Link Analysis
Final Form of Analog Free Space RF Link Equation Pr = EIRP*Gr/(Ls*M*Lo) (watts)
Digital Link Equation Eb/No = EIRP*Gr/(R*k*To*Ls*M*Lo) (dimensionless)