1. Electrical Communications Systems ECE.09.433 Spring 2019
Lecture 6a February 26, 2019
Shreekanth Mandayam
ECE Department
Rowan University

2. Plan Angle Modulation Systems
Left Behind: SSB Modulation
Hilbert Transform
Angle Modulation Systems
Definitions - Phase and Frequency Modulation
Complex Envelope
Time Domain
Analyzing FM Signals - Battle Plan!!!!
Single-tone FM

3. ECOMMS: Topics

4. Single Sideband (SSB) Modulation
Recall: DSB-SC Spectrum
USSB - Signal with zero-valued spectrum for |f| < fc
LSSB - Signal with zero-valued spectrum for |f| > fc
-fc-B -fc fc+B fc-B fc fc+B
|S(f)| f

5. The Hilbert Transform time, t in sec -1 -0.5 0.5 1 1.5 2 3 4 5 6 7
0.5 1
1.5 2 3 4 5 6 7
time, t in sec
» t=0:0.1:2*pi;
» w=sin(t);
» plot(t,w)
» hold
Current plot held
» H=hilbert(w);
» plot(t,imag(H),'r');
» xlabel('time, t in sec')

6. SSB Generation S Phasing Method Filter Method m(t) s(t) m(t) s(t)
Product
Modulator
Carrier
-90o
Phase Shift
m(t) S
s(t)
Filter Method
Sideband
Filter
Carrier
Product
Modulator
m(t)
s(t)

7. SSB Generation: Weaver’s Method

8. Angle Modulation Systems
Phase Modulation (PM) Frequency Modulation(FM)
Instrument Demo
Signal Representation
Complex Envelope
Time Domain Representation
Terminology
Phase Sensitivity
Frequency Deviation
Instantaneous Frequency
Phase & Frequency Modulation Indices
Matlab Demo:
anglemod.m

9. Analyzing FM Signals - Battle Plan!!!
Instrument Demo
Signals Systems
Time Domain
Complex Envelope
Spectrum
Single-tone FM
Narrowband FM
Wideband FM
Bessel Functions
Power
Performance
Transmitters
Receivers
Standards
Modulation
Index
Efficiency
Bandwidth
Noise

10. Summary