Computer Fundamentals Multiple choice Questions and Answers on Multiplexing for Freshers

1. WDM stands for?

a) Wave division multiplexing
b) Wavelength division multiplexing
c) Wavelength dependent multiplexing
d) Wave dependent multiplexing

Answer: b

Explanation: It stands for Wavelength division multiplexing. It has same general architecture as FDM. FDM is frequency division multiplexing.

2. In TDM, the samples occupy adjacent time slots.

a) True
b) False

Answer: a

Explanation: The statement is true. The TDM technique is based on sampling and they occupy adjacent slots and are transmitted in a sequence.

3. In this type of multiplexing time slots are preassigned to sources and fixed.

a) TDM
b) Synchronous TDM
c) Asynchronous TDM
d) FDM

Answer: b

Explanation: TDM is time division multiplexing. Data rate of medium exceeds data rate of digital signal to be transmitted.

4. Controlling the frequency is referred as _________

a) frequency modulation
b) hertz modulation
c) amplitude modulation
d) phase modulation

Answer: a

Explanation: It is referred to as frequency modulation. When there is a change in frequency, it is referred to as frequency modulation.

5. A technique that can be a solution to the problem of synchronizing data sources.

a) framing
b) data link control
c) full link control
d) pulse stuffing

Answer: d

Explanation: Pulse stuffing is a technique that can be a solution to the problem of synchronizing data sources. In pulse stuffing, the outgoing data rate is higher than sum of incoming rates.

6. For voice, each channel contains a ___ word of digitized data.

a) 2
b) 1
c) 0
d) 4

Answer: b

Explanation: In digital carrier systems, for voice each channel contains one word of digitized data. The data rate is 1.544 Mbps. Five out of six frames have 8 bit PCM samples.

7. Many time slots are wasted in __________

a) TDM
b) Synchronous TDM
c) Asynchronous TDM
d) FDM

Answer: b

Explanation: In Synchronous TDM, many time slots are wasted. Other techniques can help overcome this problem.

8. A technique that allocates time slots dynamically.

a) TDM
b) WDM
c) Dynamic TDM
d) Statistical TDM

Answer: d

Explanation: Statistical TDM assigns time slots dynamically. They are allocated based on demand. Multiplexer scans input lines and collects data until the frame is full.

9. A system in which two channels are dedicated to transfer data.

a) TV
b) Cable
c) Modem
d) Cable modem

Answer: d

Explanation: A cable modem has two dedicated channels from cable TV provider dedicated to data transfer. One in each direction.

10. In this technique, there is a link between subscriber and network and a local loop.

a) SSDL
b) DSDL
c) ASDL
d) TSDL

Answer: c

Explanation: In ASDL, there is a link between the subscriber and the network. It uses currently installed twisted pair cable.