Given the following statements : (A) Frequency Division Multiplexing is a…
2016
Given the following statements :
(A) Frequency Division Multiplexing is a technique that can be applied when the bandwidth of a link is greater than combined bandwidth of signals to be transmitted.
(B) Wavelength Division Multiplexing (WDM) is an analog multiplexing Technique to combine optical signals.
(C) WDM is a Digital Multiplexing Technique.
(D) TDM is a Digital Multiplexing Technique. Which of the following is correct ?
- A.
(A), (B), (C) and (D) are true.
- B.
(A), (B), (C) and (D) are false.
- C.
(A), (B) and (D) are false; (C) is true.
- D.
(A), (B) and (D) are True; (C) is false.
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Correct answer: D
Answer: The statements that Frequency Division Multiplexing and Time Division Multiplexing are true; Wavelength Division Multiplexing should be treated as a carrier/wavelength-based technique (true as stated), and the claim that WDM is strictly digital is false.
Frequency Division Multiplexing (FDM) applicability — True. FDM assigns separate frequency bands to each signal, so it requires the link bandwidth to be greater than the combined bandwidth of the signals to avoid overlap.
Wavelength Division Multiplexing (WDM) characterization — True (but with nuance). WDM combines multiple optical carriers at different wavelengths, analogous to FDM in the optical domain. It is often described as a carrier-based (analog-style) multiplexing technique because it separates channels by wavelength, but the channels themselves can carry either analog or digital information.
Claim that WDM is a digital multiplexing technique — False. WDM is not limited to digital signals; it is a physical-layer method of separating channels by wavelength and can carry both analog and digital channels, so calling it strictly digital is incorrect.
Time Division Multiplexing (TDM) — True. TDM allocates time slots to different signals and is commonly used for multiplexing digitally encoded channels, so it is classified as a digital multiplexing technique in typical communication systems.
Therefore, the correct selection is the one that states that the frequency- and wavelength-based statements and TDM are true while the statement claiming WDM is strictly digital is false.
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