MCQOPTIONS
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MCQOPTIONS
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. |
Flat fading can be avoided or stopped by |
| A. | Error coding |
| B. | Equalization |
| C. | Adaptive bit loading |
| D. | All of the mentioned |
| Answer» E. | |
| 2. |
If coherence bandwidth is smaller than the bandwidth of the signal, _____ fading occurs. |
| A. | Flat |
| B. | Frequency selective |
| C. | Fast fading |
| D. | Time selective |
| Answer» C. Fast fading | |
| 3. |
Block fading occurs in |
| A. | Frequency domain |
| B. | Time domain |
| C. | Frequency & Time domain |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 4. |
Coherence time is _______ to Doppler spread. |
| A. | Directly proportional |
| B. | Inversely proportional |
| C. | Not dependent |
| D. | None of the mentioned |
| Answer» C. Not dependent | |
| 5. |
When a user’s moving, the user’s velocity causes shift in frequency. This is called as |
| A. | Doppler shift |
| B. | Frequency shift |
| C. | Velocity shift |
| D. | None of the mentioned |
| Answer» B. Frequency shift | |
| 6. |
Channel’s time spreading properties are |
| A. | Coherence bandwidth |
| B. | Signal dispersion |
| C. | Coherence bandwidth & Signal dispersion |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 7. |
BLOCK_FADING_OCCURS_IN?$ |
| A. | Frequency domain |
| B. | Time domain |
| C. | Frequency & Time domain |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 8. |
COHERENCE_TIME_IS_________TO_DOPPLER_SPREAD.?$ |
| A. | Directly proportional |
| B. | Inversely proportional |
| C. | Not dependent |
| D. | None of the mentioned |
| Answer» C. Not dependent | |
| 9. |
Flat fading can be avoided or stopped by$ |
| A. | Error coding |
| B. | Equalization |
| C. | Adaptive bit loading |
| D. | All of the mentioned |
| Answer» E. | |
| 10. |
If coherence bandwidth is smaller than the bandwidth of the signal, _____ fading occurs.$ |
| A. | Flat |
| B. | Frequency selective |
| C. | Fast fading |
| D. | Time selective |
| Answer» C. Fast fading | |
| 11. |
Frequency tracking loop can minimize irreducible error rate by using |
| A. | GMSK |
| B. | DMSK |
| C. | MSK |
| D. | QAM |
| Answer» C. MSK | |
| 12. |
If signalling rate is less than fading rate, _____ fading occurs. |
| A. | Slow |
| B. | Fast |
| C. | Time selective |
| D. | None of the mentioned |
| Answer» C. Time selective | |
| 13. |
When transmitter and receiver moves towards each other, the magnitude of frequency shift is |
| A. | Positive |
| B. | Negative |
| C. | Zero |
| D. | Infinity |
| Answer» B. Negative | |
| 14. |
The effect of Doppler shift can be counterattacked by |
| A. | OFDM |
| B. | By using two receivers with separate antennas |
| C. | By using diversity receiver |
| D. | All of the mentioned |
| Answer» E. | |
| 15. |
When a user’s moving, the user’s velocity causes shift in frequency. This is called a?# |
| A. | Doppler shift |
| B. | Frequency shift |
| C. | Velocity shift |
| D. | None of the mentioned |
| Answer» B. Frequency shift | |
| 16. |
Minimum time required for magnitude change or phase change is called as |
| A. | Shift time |
| B. | Coherence time |
| C. | Delay time |
| D. | None of the mentioned |
| Answer» C. Delay time | |
| 17. |
When channel coherence time is less than the time duration of a transmission symbol, then ______ fading occurs. |
| A. | Fast |
| B. | Slow |
| C. | Time selective |
| D. | None of the mentioned |
| Answer» B. Slow | |
| 18. |
Channel’s time spreading properties are$ |
| A. | Coherence bandwidth |
| B. | Signal dispersion |
| C. | Coherence bandwidth & Signal dispersion |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 19. |
When channel coherence bandwidth is greater than the transmitted signal bandwidth ______ occurs. |
| A. | Time selective |
| B. | Frequency selective |
| C. | Frequency non selective |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 20. |
If delay time is lesser than symbol time, ______ fading occurs. |
| A. | Frequency non selective |
| B. | Flat |
| C. | Frequency non selective & Flat |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 21. |
If delay time is greater than symbol time, _______ fading occurs. |
| A. | Frequency selective |
| B. | Time selective |
| C. | Frequency non selective |
| D. | None of the mentioned |
| Answer» B. Time selective | |
| 22. |
Multiple isolated peaks in multipath components is called as |
| A. | Fingers |
| B. | Returns |
| C. | Fingers & Returns |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |