Modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted.
A modulator is a device that performs modulation. A demodulator (sometimes detector) is a device that performs demodulation, the inverse of modulation. A modem (from modulator–demodulator) can perform both operations.
Amplitude Modulation
To achieve amplitude modulation the amplitude of the carrier signal is made proportional to the instantaneous amplitude of the modulating signal.
Let the modulating signal’s potential denoted as
The carrier signal voltage can be denoted as
The carrier signal frequency should be much greater than the demodulating signal frequency
Resulted modulated wave has the form;
According to the above the bandwidth requirement for a amplitude modulated signal is equal to wice the frequency of the modulating signal.
H.LaaHiru.C.Fernando.
A modulator is a device that performs modulation. A demodulator (sometimes detector) is a device that performs demodulation, the inverse of modulation. A modem (from modulator–demodulator) can perform both operations.
Amplitude Modulation
To achieve amplitude modulation the amplitude of the carrier signal is made proportional to the instantaneous amplitude of the modulating signal.
Let the modulating signal’s potential denoted as
The carrier signal voltage can be denoted as
The carrier signal frequency should be much greater than the demodulating signal frequency
Resulted modulated wave has the form;
Where m (modulation index) is normally denoted as a percentage.
we can re arrange ;
H.LaaHiru.C.Fernando.
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