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Signals and Spectral Methods in Geoinformatics. Lecture 6: Signals Transmission. Signal transmission. 1 MODULATION : Placing the signal on a monochromatic signal ( carrier frequency ). 2 TRANSMISSION. 3 RECEPTION. 4 DEMODULATION : Signal recovery ( removal of carrier frequency ).
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SignalsandSpectral Methods in Geoinformatics Lecture 6: Signals Transmission
Signaltransmission 1MODULATION :Placing the signal on a monochromatic signal (carrier frequency) 2TRANSMISSION 3RECEPTION 4DEMODULATION:Signal recovery (removal of carrier frequency)
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC Α. Amplitude modulation (general form) :
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC m(t) Α. Amplitude modulation (general form) :
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC m(t) Α. Amplitude modulation (general form) : Β. Angle modulation (generalform) :
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC m(t) Α. Amplitude modulation (general form) : Β. Angle modulation (generalform) :
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC m(t) Α. Amplitude modulation (general form) : Β. Angle modulation (generalform) : Α. AM = Amplitude Modulation:
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC m(t) Α. Amplitude modulation (general form) : Β. Angle modulation (generalform) : Α. AM = Amplitude Modulation:
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC m(t) Α. Amplitude modulation (general form) : Β. Angle modulation (generalform) : Α. AM = Amplitude Modulation:
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC m(t) Α. Amplitude modulation (general form) : Β. Angle modulation (generalform) : Α. AM = Amplitude Modulation: Β. Angle modulation
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC m(t) Α. Amplitude modulation (general form) : Β. Angle modulation (generalform) : Α. AM = Amplitude Modulation: Β. Angle modulation Β1. PM = Phase Modulation: Β2. FM = Frequency Modulation:
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC m(t) Α. Amplitude modulation (general form) : Β. Angle modulation (generalform) : Α. AM = Amplitude Modulation: Β. Angle modulation Β1. PM = Phase Modulation: Β2. FM = Frequency Modulation:
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC m(t) Α. Amplitude modulation (general form) : Β. Angle modulation (generalform) : Α. AM = Amplitude Modulation: Β. Angle modulation Β1. PM = Phase Modulation: Β2. FM = Frequency Modulation:
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC m(t) Α. Amplitude modulation (general form) : Β. Angle modulation (generalform) : Α. AM = Amplitude Modulation: Β. Angle modulation Β1. PM = Phase Modulation: Β2. FM = Frequency Modulation:
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC m(t) Α. Amplitude modulation (general form) : Β. Angle modulation (generalform) : Α. AM = Amplitude Modulation: Β. Angle modulation Β1. PM = Phase Modulation: Β2. FM = Frequency Modulation:
modulation Modulation = placement of signalm(t) on a monochromatic signalxC(t) = aC cos(φ0C+ωCt) with carrier frequencyωC m(t) Α. Amplitude modulation (general form) : Β. Angle modulation (generalform) : Α. AM = Amplitude Modulation: Β. Angle modulation Β1. PM = Phase Modulation: Β2. FM = Frequency Modulation:
Example: Modulation of a sinusoidal signalm(t) = cosωt signal to be modulated
Example: Modulation of a sinusoidal signalm(t) = cosωt signal to be modulated carrier frequency
AM Example: Modulation of a sinusoidal signalm(t) = cosωt signal to be modulated carrier frequency amplitude modulation
AM PM Example: Modulation of a sinusoidal signalm(t) = cosωt signal to be modulated carrier frequency amplitude modulation phase modulation
AM FM PM Example: Modulation of a sinusoidal signalm(t) = cosωt signal to be modulated carrier frequency amplitude modulation phase modulation frequency modulaion
AM FM PM Example: Modulation of a sinusoidal signalm(t) = cosωt signal to be modulated carrier frequency amplitude modulation phase modulation frequency modulaion
demodulation Demodulation = separation of main signalm(t)from the received modulated signalx(t)
demodulation Demodulation = separation of main signalm(t)from the received modulated signalx(t) Spectrum of signalm(t) = Fourier transform :
demodulation Demodulation = separation of main signalm(t)from the received modulated signalx(t) Spectrum of signalm(t) = Fourier transform :
demodulation Demodulation = separation of main signalm(t)from the received modulated signalx(t) Spectrum of signalm(t) = Fourier transform :
demodulation Demodulation = separation of main signalm(t)from the received modulated signalx(t) Spectrum of signalm(t) = Fourier transform :
demodulation Demodulation = separation of main signalm(t)from the received modulated signalx(t) Spectrum of signalm(t) = Fourier transform :
demodulation Demodulation = separation of main signalm(t)from the received modulated signalx(t) Spectrum of signalm(t) = Fourier transform :
demodulation Demodulation = separation of main signalm(t)from the received modulated signalx(t) Spectrum of signalm(t) = Fourier transform : Properties used:
demodulation Demodulation = separation of main signalm(t)from the received modulated signalx(t) Spectrum of signalm(t) = Fourier transform : Properties used: Modulation theorem
demodulation Demodulation = separation of main signalm(t)from the received modulated signalx(t) Spectrum of signalm(t) = Fourier transform : Properties used: Modulation theorem from which follows
Double Band demodulation Modulation = multiplication of the signalm(t)with the carrier frequencycosωCt
Double Band demodulation Modulation = multiplication of the signalm(t)with the carrier frequencycosωCt Demodulation= multiplication again with the carrier frequencycosωCt + low pass filter
Double Band demodulation Modulation = multiplication of the signalm(t)with the carrier frequencycosωCt Demodulation= multiplication again with the carrier frequencycosωCt + low pass filter
Double Band demodulation Modulation = multiplication of the signalm(t)with the carrier frequencycosωCt Demodulation= multiplication again with the carrier frequencycosωCt + low pass filter ω ω-ωC
Double Band demodulation Modulation = multiplication of the signalm(t)with the carrier frequencycosωCt Demodulation= multiplication again with the carrier frequencycosωCt + low pass filter ω ω-ωC ω ω+ωC
Double Band demodulation Modulation = multiplication of the signalm(t)with the carrier frequencycosωCt Demodulation= multiplication again with the carrier frequencycosωCt + low pass filter ω ω-ωC ω ω+ωC
Double Band demodulation Modulation = multiplication of the signalm(t)with the carrier frequencycosωCt Demodulation= multiplication again with the carrier frequencycosωCt + low pass filter ω ω-ωC ω ω+ωC
Double Band demodulation Modulation = multiplication of the signalm(t)with the carrier frequencycosωCt Demodulation= multiplication again with the carrier frequencycosωCt + low pass filter ω ω-ωC ω ω+ωC After the low pass filter remains:
|M(ω)| Double Band demodulation original signal
|Χ(ω)| -ωC ωC |M(ω)| Double Band demodulation original signal MODULATION modulated signal
|Χ(ω)| -ωC ωC |M(ω)| Double Band demodulation original signal MODULATION TRANSMISSION - RECEPTION modulated signal
|Χ(ω)| -ωC ωC |D(ω)| -2ωC 2ωC |M(ω)| Double Band demodulation original signal MODULATION TRANSMISSION - RECEPTION modulated signal DEMODULATION Multiplication with carrier frequency