This set of Data communication and Networking Multiple Choice Questions and Answers (MCQs) focuses on “Multiplexing Demultiplexing techniques – frequency-division multiplexing (FDM) , Time-division multiplexing (TDM) , Wavelength division multiplexing (WDM) , Mode-division multiplexing (MDM)”.
1. A multiplexer _______ several transmission streams while a demultiplexer _______ them
- combines; separates
- compresses; decompresses
- encrypts; decrypts
- separates; combines
2. One _______ can be made of many _______
- channel; paths
- path; channels
- path; links
- channel; links
3. Which of the following is a digital multiplexing method?
- FDM
- asynchronous TDM
- synchronous TDM
- b and c
4. Which is not a basic multiplexing method?
- FDM
- TDM
- WDM
- MDM
5. _______ is an analog multiplexing technique usually involving signals that are not in the visible light frequencies
- FDM
- TDM
- WDM
- MDM
6. _______ is a digital multiplexing technique usually involving signals that are not in the visible light frequencies
- FDM
- TDM
- WDM
- MDM
7. _______ is an analog multiplexing technique usually involving signals in the visible light frequencies.
- FDM
- TDM
- WDM
- MDM
8. In FDM, the bandwidth of the link must be _______ the sum of the bandwidths of the signals to be combined
- equal to
- less than
- greater than
- an order of magnitude greater than
9. In FDM, if five signals are to be multiplexed, at least _______ carriers, each of a different frequency, must be modulated
- 1
- 5
- 6
- 10
10. FDM uses _______ to prevent modulated signals from overlapping
- physical hardware devices
- carrier frequencies
- guard bands
- demultiplexers
11. In FDM, the _______ signals can all have the same frequency range
- modulating
- carrier
- modulated
- b or c
12. The FDM demultiplexer uses a series of _______ to decompose the multiplexed signal into its constituent signals,
- guard bands
- filters
- repeaters
- amplifiers
13. WDM is very similar in concept to _______.
- asynchronous TDM
- synchronous TDM
- FDM
- AM or FM
14. If the sum of the data rates of the sending devices is X, TDM can be applied when the data rate capacity of the transmission medium is _______.
- less than X
- greater than X
- one half X
- two times X
15. In _______ the multiplexer allocates exactly the same time slot to each device at all times
- synchronous TDM
- asynchronous TDM
- FDM
- WDM
16. In _______, if a device has no data to send, its time slot remains empty
- synchronous TDM
- asynchronous TDM
- FDM
- WDM
17. In synchronous TDM, a _______ is a complete cycle of time slots, including one or more slots dedicated to each sending device.
- filter
- carrier
- signal
- frame
18. What is the efficiency of a system using synchronous TDM if 2 of the 5 devices have nothing to send?
- 20%
- 50%
- 60%
- 100%
19. In synchronous TDM, if device X has data to send, the data go to _______ in the frame
- the next available slot
- a preassigned slot
- the first slot
- none of the above
20. In asynchronous TDM, if device X has data to send, the data go to _______ in the frame.
- the next available slot
- a preassigned slot
- the first slot
- none of the above
21. In synchronous TDM, if device X has no data to send, what happens to its allotted slot?
- The next device in line takes it.
- An error message is sent.
- The bit pattern 01010101 is sent.
- The slot remains empty.
22. In synchronous TDM, each frame is filled with data from the devices in a fixed order. We call this _______
- interleaving
- synchronization
- switching
- line discipline
23. _______ allow the demultiplexer to synchronize with the incoming stream
- Slots
- Framing bits
- Demultiplexing bits
- Trailers
24. In synchronous TDM, if ten devices are each sending data at the rate of 2000 bps, what is the data rate for the line carrying the multiplexed signals?
- 2000 bps
- 20,000 bps
- greater than 20,000 bps
- less than 20,000 bps
25. What is the major weakness of asynchronous TDM?
- There aren't enough slots in each frame.
- There are too many slots per frame.
- Each slot requires an address.
- All of the above
26. What is the major weakness of synchronous TDM?
- Some slots may remain empty.
- There aren't enough slots.
- The slots are too small.
- All of the above.
27. Which type of multiplexing takes data from one high-speed line and breaks it into portions that can be sent across several lower-speed lines simultaneously?
- asynchronous TDM
- synchronous TDM
- FDM
- inverse multiplexing