Electrical Communications Systems ECE.09.331 Spring 2011 Lecture 7a March 1, 2011 Shreekanth Mandayam ECE Department Rowan University http://engineering.rowan.edu/~shreek/spring11/ecomms/
Plan SSB Modulation Angle Modulation Systems Signals Systems Definitions - Phase and Frequency Modulation Complex Envelope Time Domain Analyzing FM Signals - Battle Plan!!!! Signals Systems Time Domain Complex Envelope Spectrum Power Performance Transmitters Receivers Standards Modulation Index Efficiency Bandwidth Noise
ECOMMS: Topics
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 0 fc-B fc fc+B |S(f)| f
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')
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)
SSB Generation: Weaver’s Method
ECOMMS: Topics
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
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
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
Summary