Amplitude Modulation (Large Carrier)
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C:/Users/Sepali/Documents/SubforNNandLS/Lecture635handouts/ELE635LectureFour.dviAmplitude
Modulation (Large Carrier)
If m(t)←→M(ω), then we have:
AM ←→ (1/2)[M(ω + ωc) +M(ω − ωc)] + πAc[δ(ω + ωc) + δ(ω − ωc)]
For envelope detection:
Ac +m(t) ≥ 0 for all t. Which is the same as:Ac ≥ mp
2
Whenµ > 1 only synchronous detection is possible.
Tone Modulation
Modulating signal is a sinusoid:m(t) = B cosωmt. Find the spectrum.
3
= [c cosωct+m(t)]
Demodulation of AM Signals
If m(t)←→M(ω), then we have:
AM ←→ (1/2)[M(ω + ωc) +M(ω − ωc)] + πAc[δ(ω + ωc) + δ(ω − ωc)]
For envelope detection:
Ac +m(t) ≥ 0 for all t. Which is the same as:Ac ≥ mp
2
Whenµ > 1 only synchronous detection is possible.
Tone Modulation
Modulating signal is a sinusoid:m(t) = B cosωmt. Find the spectrum.
3
= [c cosωct+m(t)]
Demodulation of AM Signals
