Đề 7 – Đề thi, câu hỏi trắc nghiệm online Truyền số liệu

1. What is the role of a channel equalizer in data transmission?

A. To amplify the signal strength.

B. To compensate for channel distortions and intersymbol interference.

C. To encrypt data for secure transmission.

D. To compress data to reduce its size.

2. Which of the following factors most significantly affects the data transmission rate in a communication channel, according to Shannon's theorem?

A. The cost of the transmission medium.

B. The distance between the sender and receiver.

C. The bandwidth of the channel and the signal-to-noise ratio.

D. The type of modulation technique used.

3. What is the purpose of channel coding in data transmission?

A. To reduce the bandwidth required for data transmission.

B. To introduce redundancy that helps in error detection and correction.

C. To encrypt data and prevent unauthorized access.

D. To compress data to minimize transmission time.

4. Which of the following is a key difference between TCP and UDP protocols?

A. TCP is faster than UDP.

B. TCP provides reliable, ordered data delivery, while UDP does not.

C. UDP supports encryption, while TCP does not.

D. TCP is primarily used for streaming media, while UDP is not.

5. What is the purpose of flow control in data transmission?

A. To ensure data packets are routed efficiently through the network.

B. To prevent the sender from overwhelming the receiver with data.

C. To encrypt data for secure transmission.

D. To compress data to reduce transmission time.

6. What is the primary purpose of data compression in data transmission?

A. To encrypt data for secure transmission.

B. To reduce the amount of data that needs to be transmitted.

C. To detect and correct errors in data.

D. To increase the data transmission rate.

7. Which of the following is a disadvantage of using satellite communication for data transmission?

A. Limited bandwidth availability.

B. High propagation delay.

C. Susceptibility to atmospheric conditions.

D. High cost of ground equipment.

8. What is the main difference between synchronous and asynchronous data transmission?

A. Synchronous transmission is slower than asynchronous transmission.

B. Synchronous transmission requires a clock signal, while asynchronous transmission does not.

C. Asynchronous transmission is more reliable than synchronous transmission.

D. Synchronous transmission is used for short distances, while asynchronous transmission is used for long distances.

9. What is the primary function of a line code in data transmission?

A. To encrypt data for secure transmission.

B. To shape the signal spectrum for efficient transmission and synchronization.

C. To compress data to reduce its size.

D. To detect and correct errors in the transmitted data.

10. What is the primary function of a modem in data transmission?

A. To amplify the signal strength of digital signals.

B. To convert analog signals to digital signals and vice versa.

C. To filter out unwanted noise from the data stream.

D. To encrypt data for secure transmission.

11. Which of the following is a characteristic of serial data transmission?

A. Multiple bits are sent simultaneously over multiple wires.

B. Bits are sent one after another over a single channel.

C. Data is transmitted in large blocks at high speed.

D. Data transmission requires complex synchronization protocols.

12. Which of the following is a key advantage of using microwave transmission for data communication?

A. Lower cost compared to fiber optic cables.

B. Ability to transmit data over long distances without cables.

C. Immunity to electromagnetic interference.

D. Higher bandwidth than fiber optic cables.

13. What is the function of a CRC (Cyclic Redundancy Check) in data transmission?

A. To encrypt data for secure transmission.

B. To compress data to reduce its size.

C. To detect errors in the transmitted data.

D. To increase the data transmission rate.

14. What is the role of a data buffer in data transmission?

A. To amplify the signal strength of the data.

B. To temporarily store data to accommodate differences in data rates or processing speeds.

C. To encrypt data for secure transmission.

D. To compress data to reduce its size.

15. Which modulation technique is most bandwidth-efficient?

A. Amplitude Modulation (AM)

B. Frequency Modulation (FM)

C. Quadrature Amplitude Modulation (QAM)

D. Phase Modulation (PM)

16. What is the role of a codec in multimedia data transmission?

A. To amplify audio and video signals.

B. To convert data between analog and digital formats.

C. To compress and decompress audio and video data.

D. To encrypt multimedia content for security.

17. Which of the following is a characteristic of circuit switching?

A. Data is transmitted in packets.

B. Bandwidth is dynamically allocated.

C. A dedicated path is established between sender and receiver.

D. It is more efficient for bursty data traffic.

18. In the context of data transmission, what does the term 'jitter' refer to?

A. The amplitude of the transmitted signal.

B. The variation in delay between received packets.

C. The frequency of the carrier signal.

D. The level of encryption applied to the data.

19. What is the main purpose of ARQ (Automatic Repeat Request) protocols in data transmission?

A. To compress data before transmission.

B. To encrypt data for secure transmission.

C. To ensure reliable data delivery through error detection and retransmission.

D. To increase the data transmission rate.

20. Which of the following is a common technique for mitigating the effects of multipath fading in wireless data transmission?

A. Increasing the transmission power.

B. Using higher carrier frequencies.

C. Employing diversity techniques.

D. Reducing the data transmission rate.

21. What is the purpose of spread spectrum techniques in data transmission?

A. To reduce the bandwidth required for data transmission.

B. To increase the signal-to-noise ratio.

C. To resist interference and jamming.

D. To encrypt data for secure transmission.

22. What is the purpose of forward error correction (FEC) in data transmission?

A. To detect errors and request retransmission.

B. To correct errors at the receiver without retransmission.

C. To encrypt data for secure transmission.

D. To compress data to reduce its size.

23. Which of the following is a major challenge in underwater acoustic data transmission?

A. High bandwidth availability.

B. Low propagation speed of sound.

C. Minimal signal attenuation.

D. Lack of multipath fading.

24. Which of the following is a characteristic of baseband transmission?

A. It uses a carrier signal to transmit data.

B. The entire bandwidth of the transmission medium is used for a single signal.

C. It is suitable for long-distance communication.

D. It allows multiple signals to be transmitted simultaneously.

25. What is the primary function of a multiplexer in data transmission?

A. To amplify the signal strength.

B. To combine multiple data streams into a single channel.

C. To detect and correct errors in data.

D. To encrypt data for security.

26. Which of the following is a characteristic of broadband transmission?

A. It uses the entire bandwidth for a single signal.

B. It transmits digital signals directly without modulation.

C. It allows multiple channels to be transmitted simultaneously.

D. It is limited to short-distance communication.

27. What is the primary advantage of using fiber optic cables for data transmission?

A. Lower cost compared to copper cables.

B. Higher bandwidth and lower signal attenuation.

C. Easier installation and maintenance.

D. Immunity to electromagnetic interference.

28. What is the role of a demultiplexer in data transmission?

A. To combine multiple data streams into a single channel.

B. To separate a single data stream into multiple streams.

C. To amplify the signal strength.

D. To encrypt data for security.

29. Which of the following is an advantage of using packet switching over circuit switching?

A. Lower overhead for call setup.

B. Guaranteed bandwidth for the duration of the connection.

C. More efficient use of network resources.

D. Lower delay for real-time applications.

30. Which of the following is a key advantage of using time-division multiplexing (TDM) for data transmission?

A. Simpler implementation compared to frequency-division multiplexing (FDM).

B. More efficient use of bandwidth when traffic is bursty.

C. Lower cost compared to FDM.

D. Better performance with analog signals.