Vodafone Chair Mobile Communications Systems, Prof. Dr.-Ing. G. Fettweis
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Introduction to Communications:
Amplitude Modulation
Prof. Dr.-Ing. Gerhard Fettweis
Chair Mobile Communications Systems, TU Dresden
Amplitude Modulation as Mixing
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• Advantage: simple transmitter.
• Lack of phase information when using simple mixing and
envelope detector.
• For correct demodulation we need both amplitude and phase
of the carrier.
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TU Dresden,
Gerhard Fettweis
<Result>
Slide 2
Amplitude Modulation (µ>1)
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• Modulation index µ>1.
• Carrier is still pre-modulated.
• The effect of pre-modulation is seen at the receiver as added noise.
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TU Dresden,
Gerhard Fettweis
<Result>
Slide 3
Amplitude Modulation (µ≤1)
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μ
• Modulation index µ<1.
• Receiver correctly detects amplitude of the modulating signal.
• We can hear the original signal without deviation.
Start playing audio
TU Dresden,
Gerhard Fettweis
<Result>
Slide 4