UGC NET - Data communication fundamentals: signals, bandwidth, modulation, multiplexing, transmission media and error handling. Online Test (MCQ Quiz)

1. What is the primary function of bandwidth in data communication?

A) To determine the speed of data transmission B) To measure the distance data can travel C) To define the type of modulation used D) To specify the security protocol

2. Which type of signal is characterized by a continuous range of amplitude and time values?

A) Digital signal B) Analog signal C) Square wave signal D) Pulse code modulated signal

3. What does modulation in data communication refer to?

A) Combining multiple signals onto a single channel B) Converting analog signals to digital signals C) Encoding information onto a carrier signal D) Detecting and correcting errors in transmission

4. Which multiplexing technique divides the bandwidth of a channel into smaller, non-overlapping frequency bands?

A) Time Division Multiplexing (TDM) B) Frequency Division Multiplexing (FDM) C) Code Division Multiplexing (CDM) D) Statistical Time Division Multiplexing (STDM)

5. Which transmission medium uses light pulses to transmit data over glass or plastic fibers?

A) Coaxial cable B) Twisted-pair cable C) Fiber optic cable D) Microwave transmission

6. What is the purpose of error handling in data communication?

A) To increase the transmission speed B) To ensure the integrity and accuracy of transmitted data C) To reduce the cost of network infrastructure D) To compress the data before transmission

7. A signal with a frequency of 100 Hz and 1000 Hz is transmitted. What is the bandwidth of this signal?

A) 900 Hz B) 1100 Hz C) 100 Hz D) 1000 Hz

8. Which modulation technique varies the amplitude of the carrier wave in accordance with the message signal?

A) Frequency Modulation (FM) B) Phase Modulation (PM) C) Amplitude Modulation (AM) D) Quadrature Amplitude Modulation (QAM)

9. In Time Division Multiplexing (TDM), how is channel access managed?

A) Each user gets a dedicated frequency band B) Each user is assigned a specific time slot C) Users share the channel based on their codes D) The channel is divided based on the signal's phase

10. Which of the following is a guided transmission medium?

A) Radio waves B) Infrared waves C) Microwaves D) Twisted-pair cable

11. What is a common method for detecting errors in transmitted data?

A) Parity checking B) Data compression C) Signal amplification D) Frequency hopping

12. What is the unit of bandwidth?

A) Hertz (Hz) B) Bits per second (bps) C) Bytes (B) D) Volts (V)

13. Which type of signal represents data as discrete values (e.g., 0s and 1s)?

A) Analog signal B) Digital signal C) Sine wave signal D) Carrier wave signal

14. Demodulation is the process of:

A) Encoding data onto a carrier signal B) Extracting the original message signal from the modulated carrier C) Combining multiple signals into one D) Detecting and correcting transmission errors

15. Which multiplexing technique allows multiple users to share the same frequency band simultaneously by assigning unique codes to each user's signal?

A) FDM B) TDM C) CDM D) WDM

16. Which transmission medium is susceptible to electromagnetic interference (EMI)?

A) Fiber optic cable B) Coaxial cable C) Microwave D) Satellite link

17. What is the primary goal of error correction codes (ECC)?

A) To detect errors and request retransmission B) To detect errors and correct them without retransmission C) To compress data to reduce transmission time D) To encrypt data for security

18. A communication channel has a capacity of 10 Mbps. This refers to its:

A) Bandwidth B) Maximum data rate C) Attenuation D) Latency

19. What is the process of converting a digital signal into an analog signal for transmission over an analog channel called?

A) Modulation B) Demodulation C) Encoding D) Decoding

20. Which type of TDM assigns time slots dynamically based on demand?

A) Synchronous TDM B) Asynchronous TDM C) Statistical TDM D) Orthogonal TDM

21. Which transmission medium offers the highest data transmission rates and is immune to EMI?

A) Coaxial cable B) Twisted-pair cable C) Fiber optic cable D) Infrared transmission

22. What does a checksum typically provide in error handling?

A) A means to correct errors directly B) A simple method for error detection C) A way to encrypt data D) A method for signal amplification

23. The range of frequencies available for a communication channel is known as:

A) Amplitude B) Phase C) Bandwidth D) Wavelength

24. Amplitude Shift Keying (ASK) is a form of:

A) Digital modulation B) Analog modulation C) Multiplexing D) Error detection

25. In FDM, guard bands are used to:

A) Increase the number of channels B) Prevent interference between adjacent channels C) Improve signal strength D) Detect errors

26. Which unguided transmission medium uses electromagnetic waves that travel in a straight line and are often used for point-to-point communication?

A) Radio waves B) Microwaves C) Infrared waves D) Satellite links

27. What is the 'Hamming distance' used for in error control coding?

A) Measuring signal attenuation B) Determining the minimum number of bit changes required to transform one codeword into another C) Calculating the maximum data rate D) Estimating the transmission delay

28. A signal that varies continuously over time and amplitude is called:

A) Digital B) Discrete C) Analog D) Binary

29. Which modulation technique encodes data by changing the frequency of the carrier wave?

A) AM B) FM C) PM D) ASK

30. In statistical TDM, if a time slot is not needed by a source, it is:

A) Assigned to another source immediately B) Left empty and wasted C) Used for error checking D) Reserved for future use

31. Which of the following is an example of an unguided transmission medium?

A) Ethernet cable B) Fiber optic cable C) Wi-Fi (Radio waves) D) DSL line

32. A forward error correction (FEC) code can:

A) Only detect errors B) Detect and correct errors without retransmission C) Increase the bandwidth required D) Reduce the data rate

33. The maximum rate at which data can be transmitted over a communication channel is limited by its:

A) Modulation scheme B) Bandwidth and noise level C) Error detection method D) Type of multiplexing

34. What is the process of converting an analog signal to a digital signal called?

A) Modulation B) Demodulation C) Encoding D) Digitization (or Analog-to-Digital Conversion)

35. Which of the following is a characteristic of Quadrature Amplitude Modulation (QAM)?

A) It only varies the amplitude of the carrier signal. B) It only varies the frequency of the carrier signal. C) It varies both the amplitude and phase of the carrier signal. D) It is a form of Frequency Division Multiplexing.

36. Which multiplexing technique uses orthogonal codes to separate signals, allowing them to share the same frequency band and time?

A) FDM B) TDM C) CDM D) WDM

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

A) Lower cost compared to copper cables B) Higher susceptibility to electromagnetic interference C) Greater bandwidth and lower signal attenuation D) Easier installation and maintenance

38. What is a 'parity bit' used for?

A) To speed up data transmission B) To encrypt the data C) To detect single-bit errors D) To compress the data

39. The difference between the highest and lowest frequencies in a continuous band of frequencies is called:

A) Amplitude B) Wavelength C) Bandwidth D) Signal strength

40. Which modulation technique is used in traditional radio broadcasting (like FM radio)?

A) Amplitude Modulation (AM) B) Frequency Modulation (FM) C) Phase Modulation (PM) D) Amplitude Shift Keying (ASK)

41. What is a potential disadvantage of Synchronous TDM?

A) It requires complex coding schemes. B) It is inefficient if data sources are not continuously active. C) It cannot handle multiple users simultaneously. D) It is highly susceptible to noise.

42. Which guided medium consists of a central conductor surrounded by an insulator and a braided metallic shield?

A) Twisted-pair cable B) Coaxial cable C) Fiber optic cable D) Waveguide

43. Which error handling technique involves sending a block of data and then calculating a value based on the data, which is transmitted along with it?

A) Parity check B) Checksum C) Cyclic Redundancy Check (CRC) D) Forward Error Correction (FEC)

44. A signal with a bandwidth of 100 kHz can theoretically carry how many bits per second if the channel is noise-free (Shannon-Hartley theorem related concept)?

A) Limited by modulation scheme B) Infinite C) Directly proportional to bandwidth D) Dependent on signal amplitude

45. Which of the following is a type of digital modulation?

A) AM B) FM C) PSK (Phase Shift Keying) D) None of the above

46. In Wavelength Division Multiplexing (WDM), different signals are transmitted using:

A) Different time slots B) Different frequencies C) Different wavelengths of light D) Different codes

47. Which type of cable consists of two insulated copper wires twisted together?

A) Coaxial cable B) Ethernet cable (often UTP) C) Fiber optic cable D) Shielded Twisted Pair (STP)

48. What is the purpose of a Cyclic Redundancy Check (CRC)?

A) To increase data transmission speed B) To provide a more robust error detection mechanism than simple parity or checksums C) To encrypt the data for security D) To compress the data before transmission

49. The term 'signal-to-noise ratio' (SNR) is a measure of:

A) The desired signal strength relative to background noise B) The bandwidth of the channel C) The speed of data transmission D) The accuracy of modulation

50. Which modulation technique is used to transmit digital data over telephone lines (e.g., in modems)?

A) Frequency Modulation (FM) B) Amplitude Modulation (AM) C) Phase Shift Keying (PSK) and Quadrature Amplitude Modulation (QAM) D) Pulse Code Modulation (PCM)

Data communication fundamentals: signals, bandwidth, modulation, multiplexing, transmission media and error handling. - Online Test

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