Explore topic-wise MCQs in Digital Communications.

This section includes 22 Mcqs, each offering curated multiple-choice questions to sharpen your Digital Communications knowledge and support exam preparation. Choose a topic below to get started.

1.

In which modulation schemes, the spreading of spectrum occurs?

A. Frequency modulation
B. Amplitude modulation
C. Frequency & Amplitude modulation
D. None of the mentioned
Answer» B. Amplitude modulation
2.

In Aloha technique, the re-transmission takes place immediately.

A. True
B. False
Answer» C.
3.

Which technique needs precise synchronization?

A. TDMA
B. FDMA
C. TDMA & FDMA
D. None of the mentioned
Answer» B. FDMA
4.

Uncertainty in the delay measurement is _______ to rise time of the pulse.

A. Directly proportional
B. Inversely proportional
C. Not related
D. None of the mentioned
Answer» B. Inversely proportional
5.

For a throughput of value less than 0.20, which has less average delay?

A. S-ALOHA
B. Pure ALOHA
C. R-ALOHA
D. None of the mentioned
Answer» B. Pure ALOHA
6.

Which are non orthogonal multiplexing?

A. TDM
B. FDM
C. TDM & FDM
D. None of the mentioned
Answer» E.
7.

A mechanism for breaking the problem down is

A. Layering
B. Dividing
C. Abstraction
D. Entity sharing
Answer» D. Entity sharing
8.

CDMA uses

A. Hard hand off
B. Soft hand off
C. Hard & Soft hand off
D. None of the mentioned
Answer» C. Hard & Soft hand off
9.

CDMA rejects

A. Narrow band interference
B. Wide band interference
C. Narrow & Wide band interference
D. None of the mentioned
Answer» B. Wide band interference
10.

The minimum packet size of Ethernet is

A. 81 bytes
B. 75 bytes
C. 72 bytes
D. 64 bytes
Answer» D. 64 bytes
11.

Which is more costlier?

A. TDMA
B. FDMA
C. ALOHA
D. None of the mentioned
Answer» B. FDMA
12.

In SPADE system, the carrier is done based on

A. Fixed assignment
B. Demand assignment
C. Fixed & Demand assignment
D. None of the mentioned
Answer» C. Fixed & Demand assignment
13.

Minimum packet size increases as

A. Speed increases
B. Distance increases
C. Speed & Distance increases
D. None of the mentioned
Answer» D. None of the mentioned
14.

Companding is used to

A. Increase the information transmission rate
B. Use only one carrier frequency to handle different signals
C. To use different frequency bands for different signals
D. To protect all small signals in PCM from quantizing noise
Answer» E.
15.

In which technique, packet size are constant?

A. Pure Aloha
B. Slotted Aloha
C. Pure & Slotted Aloha
D. None of the mentioned
Answer» B. Slotted Aloha
16.

The preamble consists of

A. Synchronization
B. Addressing
C. Error control sequence
D. All of the mentioned
Answer» E.
17.

Which method is efficient?

A. Fixed assignment
B. Dynamic allocation
C. Fixed assignment & Dynamic allocation
D. None of the mentioned
Answer» C. Fixed assignment & Dynamic allocation
18.

In spread spectrum technique, the desired signal is multiplied _____ and interference signal is multiplied _____

A. Once, twice
B. Twice, once
C. Twice, thrice
D. Thrice, twice
Answer» C. Twice, thrice
19.

For a throughput value of 0.20 to 0.67, which has less average delay?

A. S-ALOHA
B. Pure ALOHA
C. R-ALOHA
D. None of the mentioned
Answer» D. None of the mentioned
20.

Each satellite has ______ transponders.

A. 10
B. 12
C. 15
D. 18
Answer» C. 15
21.

In digital communication, interaction between ______ is possible.

A. Any layer to layer
B. One layer to next layer
C. layers
D. None of the mentioned
Answer» C. layers
22.

Frequency planning is very essential in

A. FDMA
B. TDMA
C. FDMA & TDMA
D. None of the mentioned
Answer» D. None of the mentioned