Which modulation technique is applied to a binary signal in figure (a) to…
20212021
Which modulation technique is applied to a binary signal in figure (a) to achieve figure (b)?
- A.
Amplitude modulation
- B.
Frequency modulation
- C.
Phase modulation
- D.
Quadrature Phase Shift Keying (QPSK)
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Correct answer: A
In figure (b), we can see that the carrier wave changes its amplitude (its height/strength) based on the binary input from figure (a):
Binary '1': A carrier sine wave is present at a specific amplitude.
Binary '0': The carrier wave is absent (the amplitude is zero).
This specific type of AM, where the carrier is switched completely "on" or "off," is often called On-Off Keying (OOK).