MCQOPTIONS
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MCQOPTIONS
This section includes 78 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. |
Digital system includes |
| A. | Better encryption algorithm |
| B. | Difficult data multiplexing |
| C. | All of the mentioned |
| D. | None of the mentioned |
| Answer» B. Difficult data multiplexing | |
| 2. |
As the order of the filter increases, the cost ______ and complexity ______ |
| A. | Increases, increases |
| B. | Increases, decreases |
| C. | Decreases, increases |
| D. | Decreases, decreases |
| Answer» B. Increases, decreases | |
| 3. |
What are the characteristics of an ideal transmission line? |
| A. | Different amplitude |
| B. | No distortion |
| C. | Time delay |
| D. | All of the mentioned |
| Answer» E. | |
| 4. |
Autocorrelation is a function which matches |
| A. | Two same signals |
| B. | Two different signal |
| C. | One signal with its delayed version |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 5. |
Matched filter can also be used as least squares estimator. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 6. |
Modulation channel does not accept an analog input signal. |
| A. | True |
| B. | False |
| Answer» C. | |
| 7. |
Thermal noise is |
| A. | Energy signal |
| B. | Power signal |
| C. | Energy & Power signal |
| D. | None of the mentioned |
| Answer» C. Energy & Power signal | |
| 8. |
Which is practically realizable? |
| A. | A train of pulses |
| B. | Impulse train |
| C. | All of the mentioned |
| D. | None of the mentioned |
| Answer» B. Impulse train | |
| 9. |
A unit impulse function has? |
| A. | Large amplitude |
| B. | Zero pulse width |
| C. | Unity weight |
| D. | All of the mentioned |
| Answer» E. | |
| 10. |
Analog to digital conversion includes |
| A. | Sampling |
| B. | Quantization |
| C. | Sampling & Quantization |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 11. |
Sampling theorem is used for converting |
| A. | Continuous time signal to discrete |
| B. | Discrete to continuous time signal |
| C. | Continuous time signal to discrete & vice versa |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 12. |
Transmission media used for medium frequency band are |
| A. | Coaxial cable |
| B. | Copper cable |
| C. | Optical fiber |
| D. | All of the mentioned |
| Answer» C. Optical fiber | |
| 13. |
Standard deviation is ______ |
| A. | Rms value of dc |
| B. | Rms value or ac |
| C. | Either ac or dc |
| D. | Neither dc nor ac |
| Answer» C. Either ac or dc | |
| 14. |
Source coding block is used for? |
| A. | Compressing |
| B. | Digitizing |
| C. | A/D conversion |
| D. | All of the mentioned |
| Answer» E. | |
| 15. |
The autocorrelation function is maximum at |
| A. | Origin |
| B. | Infinity |
| C. | Origin & Infinity |
| D. | None of the mentioned |
| Answer» B. Infinity | |
| 16. |
The average power of white noise is |
| A. | Zero |
| B. | Unity |
| C. | Infinity |
| D. | Between zero and one |
| Answer» D. Between zero and one | |
| 17. |
The ratio of the filter bandwidth at -60db and -6db amplitude response point is called as _____ |
| A. | Half point factor |
| B. | Normalized factor |
| C. | Shape factor |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 18. |
Synchronization available in digital communication are |
| A. | Symbol synchronization |
| B. | Frame synchronization |
| C. | Carrier synchronization |
| D. | All of the mentioned |
| Answer» E. | |
| 19. |
Capacity of the channel can be increased by reducing in band noise power. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 20. |
Autocorrelation is a function of |
| A. | Time |
| B. | Frequency |
| C. | Time difference |
| D. | Frequency difference |
| Answer» D. Frequency difference | |
| 21. |
A signal can be recovered from its sample by using |
| A. | Low pass filter |
| B. | High pass filter |
| C. | Band pass filter |
| D. | Band stop filter |
| Answer» B. High pass filter | |
| 22. |
For the number of bits, k=1 and number of symbols, M=2 the system is called as |
| A. | Unary |
| B. | Binary |
| C. | Quarternary |
| D. | None of the mentioned |
| Answer» C. Quarternary | |
| 23. |
Which are the common transmission media used in digital communication system? |
| A. | Coaxial cable |
| B. | Twisted copper cable |
| C. | Radio frequency bands |
| D. | All of the mentioned |
| Answer» E. | |
| 24. |
Fourier transform of a signal gives the |
| A. | Frequency content |
| B. | Bandwidth |
| C. | Frequency content & Bandwidth |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 25. |
Loop filter is a ______ used to reduce noise. |
| A. | Low pass filter |
| B. | High pass filter |
| C. | Band pass filter |
| D. | Band reject filter |
| Answer» B. High pass filter | |
| 26. |
Determine the periodicity and also find whether it is a power or energy signal? e(-at)u(t) |
| A. | Periodic and energy signal |
| B. | Non periodic and energy signal |
| C. | Periodic and power signal |
| D. | Periodic and energy signal |
| Answer» C. Periodic and power signal | |
| 27. |
Ionospheric communication can take place in |
| A. | High frequency band |
| B. | Very high frequency band |
| C. | Ultra high frequency band |
| D. | Super high frequency band |
| Answer» B. Very high frequency band | |
| 28. |
For a stationary process, autocorrelation function depends on |
| A. | Time |
| B. | Time difference |
| C. | Does not depend on time |
| D. | None of the mentioned |
| Answer» C. Does not depend on time | |
| 29. |
Capacity of a channel can be increased by |
| A. | Increasing channel bandwidth |
| B. | Increasing signal power |
| C. | Increasing channel bandwidth &signal power |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 30. |
The process of data conversion along with formatting the data is called as ______ |
| A. | Formatting |
| B. | Modulation |
| C. | Source coding |
| D. | Amplifying |
| Answer» D. Amplifying | |
| 31. |
A band-pass signal has a Fourier transform equal to |
| A. | One |
| B. | Zero |
| C. | Infinity |
| D. | Cannot be determined |
| Answer» C. Infinity | |
| 32. |
Discrete impulse signal is a power or energy signal? |
| A. | Power signal |
| B. | Energy signal |
| C. | Both power and energy signal |
| D. | Neither power or energy signal |
| Answer» C. Both power and energy signal | |
| 33. |
Check whether the signal is periodic or not?x(t) = cos(4t) + 2sin(8t) |
| A. | Periodic with period π/2 |
| B. | Periodic with period 2 |
| C. | Periodic with period 2/π |
| D. | Not periodic |
| Answer» B. Periodic with period 2 | |
| 34. |
The weighing matrix is |
| A. | Positive quantity |
| B. | Inverse of covariance matrix of the input vector |
| C. | Positive quantity & Inverse of a covariance matrix of the input vector |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 35. |
The size of the alphabet M in symbol is calculated as? |
| A. | 2(k+1) |
| B. | 2k |
| C. | 2(k-1) |
| D. | 1+2k |
| Answer» C. 2(k-1) | |
| 36. |
Equalizer is used for? |
| A. | Filtering |
| B. | Diminish distortion |
| C. | All of the mentioned |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 37. |
Noise has |
| A. | Infinite energy |
| B. | Infinite power |
| C. | Infinite energy & power |
| D. | None of the mentioned |
| Answer» B. Infinite power | |
| 38. |
Find the 32-ary waveform for the word 'HAPPY'. |
| A. | 280856 |
| B. | 658082 |
| C. | 288056 |
| D. | None of the mentioned |
| Answer» B. 658082 | |
| 39. |
Which measurement considers phase as an important parameter? |
| A. | Coherent |
| B. | Non-coherent |
| C. | All of the mentioned |
| D. | None of the mentioned |
| Answer» B. Non-coherent | |
| 40. |
The measure of the width of the main lobe is called as ________ |
| A. | Null to null bandwidth |
| B. | Half power bandwidth |
| C. | Normalized bandwidth |
| D. | Absolute bandwidth |
| Answer» B. Half power bandwidth | |
| 41. |
Which has the same power spectral density? |
| A. | White noise |
| B. | Brown noise |
| C. | White & Brown noise |
| D. | None of the mentioned |
| Answer» B. Brown noise | |
| 42. |
Matched filtering operation includes |
| A. | Spectral phase matching |
| B. | Spectral amplitude matching |
| C. | Spectral phase & amplitude matching |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 43. |
Thermal noise is a wide sense stationary process. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 44. |
Analog information is converted to digital data using |
| A. | Sampling |
| B. | Quantization |
| C. | Coding |
| D. | All of the mentioned |
| Answer» E. | |
| 45. |
In flat top sampling scheme, ______ is kept constant after sampling. |
| A. | Amplitude |
| B. | Phase |
| C. | Frequency |
| D. | Time period |
| Answer» B. Phase | |
| 46. |
Find the 8-ary waveform for the word 'HAPPY'. |
| A. | 4040020246 |
| B. | 440020246 |
| C. | 6420200440 |
| D. | None of the mentioned |
| Answer» C. 6420200440 | |
| 47. |
Modulation channel consists of |
| A. | Amplifier |
| B. | Signal processing units |
| C. | Amplifier & Signal processing units |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 48. |
Continuous Impulse signal is a power or energy signal? |
| A. | Power signal |
| B. | Energy signal |
| C. | Both power and energy |
| D. | Neither power nor energy signal |
| Answer» E. | |
| 49. |
Non uniform tree _____ bit rate. |
| A. | Increases |
| B. | Decreases |
| C. | Does not affect |
| D. | None of the mentioned |
| Answer» B. Decreases | |
| 50. |
The process that transforms text into binary digits is called as _______ |
| A. | Binary coding |
| B. | Data coding |
| C. | Character coding |
| D. | Sampling |
| Answer» D. Sampling | |