Amplitude Modulation Flashcards
What is the definition of modulation?
Modulation is the process where information is superimposed upon a RF carrier wave.
What is a modulating wave?
The waveform of the original intelligence/ The AF
What is the carrier wave?
Used the carry the modulating wave/ “The EM wave”
What is the modulated wave?
Wave that is created by encoding the modulating waveform onto the carrier wave.
What is the definition of Amplitude Modulation?
It is the method in which the amplitude of the modulated wave is varied in accordance wiht the amplitude of the modulated wave.
If the amplitude of the transmission stays the same it is said to have a…?
Constant envelope.
If the amplitude of the transmission varies repetitively it is said to have a…?
Periodic envelope.
What does LSF and USF stand for?
Lower sideband and Upper sideband.
What is the transmission bandwidth?
It is the difference in Hertz between the lowest and highest frequency components of the complex waveform.
How do you work out the transmission bandwidth?
2 x modulating frequency (fm)
What is depth of modulation?
It indicates a measure of how much the modulating wave affects the carrier wave, the resultant wave and frequency spectrum.
Ho do you work out the depth of modulation?
Depth of modulation = Peak AF voltage/Peak RF voltage x 100
What is a double sideband (DSB)
It is the method of operation in which both bands of frequencies are transmitted equally.
What is the frequency range of human speech?
300Hz - 3400Hz.
What is an erect sideband?
The higher the RF the higher the AF.
