MCQOPTIONS
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MCQOPTIONS
This section includes 61 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. |
The bandwidth efficiency of QFSK is _______ that of BFSK. |
| A. | Greater than |
| B. | Less than |
| C. | Equal to |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 2. |
The mixing and filtering of DSB removes |
| A. | LSB |
| B. | USB |
| C. | LSB & USB |
| D. | None of the mentioned |
| Answer» C. LSB & USB | |
| 3. |
Which modulation requires more bandwidth? |
| A. | QPSK |
| B. | OQPSK |
| C. | BPSK |
| D. | BFSK |
| Answer» D. BFSK | |
| 4. |
Which modulation spectrum has narrow main lobe? |
| A. | QPSK |
| B. | OQPSK |
| C. | BPSK |
| D. | MSK |
| Answer» B. OQPSK | |
| 5. |
The system will be more bandwidth efficient as WTb decreases. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 6. |
The bandwidth efficiency of MFSK is |
| A. | M/log2M |
| B. | log2M/M |
| C. | M/log10M |
| D. | log10M/M |
| Answer» C. M/log10M | |
| 7. |
Which provides more secure communication? |
| A. | CDMA |
| B. | FDMA |
| C. | TDMA |
| D. | None of the mentioned |
| Answer» B. FDMA | |
| 8. |
In channel encoding procedure |
| A. | Redundancy bits are added |
| B. | Errors are corrected |
| C. | Redundancy bits are added & Errors are corrected |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 9. |
Simulation is used to determine |
| A. | Bit error rate |
| B. | Symbol error rate |
| C. | Bit error |
| D. | Symbol error |
| Answer» B. Symbol error rate | |
| 10. |
Free space in idealization which consists |
| A. | Transmitter |
| B. | Receiver |
| C. | Transmitter & Receiver |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 11. |
Entropy calculation returns |
| A. | Random variable |
| B. | Deterministic number |
| C. | Random number |
| D. | None of the mentioned |
| Answer» C. Random number | |
| 12. |
Channelization characterized by orthogonal spectra is called as |
| A. | Time division multiplexing |
| B. | Frequency division multiplexing |
| C. | Time division & Frequency division multiplexing |
| D. | None of the mentioned |
| Answer» C. Time division & Frequency division multiplexing | |
| 13. |
QPSK amplitude modulates |
| A. | Sine function |
| B. | Cosine function |
| C. | Sine & Cosine function |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 14. |
Switching exists in |
| A. | Point to point communication |
| B. | Broadcast communication |
| C. | Point to point & Broadcast communication |
| D. | None of the mentioned |
| Answer» B. Broadcast communication | |
| 15. |
Coherent demodulation of FSK signal can be performed using |
| A. | Matched filter |
| B. | BPF and envelope detectors |
| C. | Discriminator |
| D. | None of the mentioned |
| Answer» B. BPF and envelope detectors | |
| 16. |
Which technique can be used for bandwidth reduction? |
| A. | BPSK |
| B. | QPSK |
| C. | MPSK |
| D. | MFSK |
| Answer» D. MFSK | |
| 17. |
The primary communication resource is |
| A. | Transmitted power |
| B. | Received power |
| C. | Efficiency |
| D. | None of the mentioned |
| Answer» B. Received power | |
| 18. |
Properties used to determine stream's fidelity |
| A. | Sampling rate |
| B. | Bit depth |
| C. | Sampling rate & Bit depth |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 19. |
Which refers to the presence of error correction coding scheme? |
| A. | Coded |
| B. | Uncoded |
| C. | Coded & Uncoded |
| D. | None of the mentioned |
| Answer» B. Uncoded | |
| 20. |
Which of the following requires a synchronizing signal? |
| A. | Single channel PPM system |
| B. | PAM |
| C. | DM |
| D. | All of the mentioned |
| Answer» C. DM | |
| 21. |
Matched filter is a _____ technique. |
| A. | Modulation |
| B. | Demodulation |
| C. | Modulation & Demodulation |
| D. | None of the mentioned |
| Answer» C. Modulation & Demodulation | |
| 22. |
QAM uses ______ as the dimensions. |
| A. | In phase |
| B. | Quadrature |
| C. | In phase & Quadrature |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 23. |
In time division system, the actual switch is called as |
| A. | Speech memory |
| B. | Cross point |
| C. | Connecting point |
| D. | None of the mentioned |
| Answer» B. Cross point | |
| 24. |
Which is called as on-off keying? |
| A. | Amplitude shift keying |
| B. | Uni-polar PAM |
| C. | Amplitude shift keying & Uni-polar PAM |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 25. |
QAM is a combination of |
| A. | ASK and FSK |
| B. | ASK and PSK |
| C. | PSK and FSK |
| D. | None of the mentioned |
| Answer» C. PSK and FSK | |
| 26. |
A PWM signal can be generated by |
| A. | An astable multi vibrator |
| B. | A monostable multi vibrator |
| C. | Integrating a PPM signal |
| D. | Differentiating a PPM signal |
| Answer» C. Integrating a PPM signal | |
| 27. |
Which modulation is the most efficient one? |
| A. | BPSK |
| B. | BFSK |
| C. | QPSK |
| D. | QAM |
| Answer» E. | |
| 28. |
Code's redundancy is given as |
| A. | n/k |
| B. | k/n |
| C. | nk |
| D. | None of the mentioned |
| Answer» B. k/n | |
| 29. |
Greater the redundancy lesser is the bandwidth expansion. |
| A. | True |
| B. | False |
| Answer» C. | |
| 30. |
A PAM signal can be detected using |
| A. | Low pass filter |
| B. | High pass filter |
| C. | Band pass filter |
| D. | All pass filter |
| Answer» B. High pass filter | |
| 31. |
How can the throughput of the system be increased? |
| A. | Increasing EIRP |
| B. | Increasing channel bandwidth |
| C. | Decreasing system losses |
| D. | All of the mentioned |
| Answer» E. | |
| 32. |
QPSK is a composite of |
| A. | Two BPSK |
| B. | Three BPSK |
| C. | Two FSK |
| D. | Two M-ary PSK |
| Answer» B. Three BPSK | |
| 33. |
In MFSK, R/W |
| A. | Increases with increase in M |
| B. | Increases with decrease in M |
| C. | Decreases with increase in M |
| D. | Is not dependent on M |
| Answer» D. Is not dependent on M | |
| 34. |
The transmission rate is given as |
| A. | R/log2M |
| B. | log2M/R |
| C. | R/log10M |
| D. | log10M/R |
| Answer» B. log2M/R | |
| 35. |
The bandwidth efficiency increases as M increases. |
| A. | True |
| B. | False |
| Answer» C. | |
| 36. |
TDM requires |
| A. | Constant data transmission |
| B. | Transmission of data samples |
| C. | Transmission of data at random |
| D. | Transmission of data of only one measured |
| Answer» C. Transmission of data at random | |
| 37. |
The super group is made up of |
| A. | Five groups |
| B. | Sixty channels |
| C. | Five groups & Sixty channels |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 38. |
In an ideal TDM system, the cross correlation between two users of the system is |
| A. | 1 |
| B. | 0 |
| C. | Infinity |
| D. | -1 |
| Answer» C. Infinity | |
| 39. |
The use of non uniform quantization leads to |
| A. | Reduction in transmission bandwidth |
| B. | Increase in maximum SNR |
| C. | Increase in SNR for low level signals |
| D. | Simplification of quantization process |
| Answer» D. Simplification of quantization process | |
| 40. |
The TCM decoder uses |
| A. | Minimum likelihood detector |
| B. | Maximum likelihood detector |
| C. | Does not use redundant bits |
| D. | None of the mentioned |
| Answer» C. Does not use redundant bits | |
| 41. |
Transmission bandwidth depends on |
| A. | Rate of signalling |
| B. | Density of signal points |
| C. | Reduced distance |
| D. | None of the mentioned |
| Answer» B. Density of signal points | |
| 42. |
Which determines the error performance in TCM? |
| A. | Reduced distance |
| B. | Free distance |
| C. | Bandwidth |
| D. | None of the mentioned |
| Answer» C. Bandwidth | |
| 43. |
Which modulation is selected for power limited system? |
| A. | MPSK |
| B. | MFSK |
| C. | MPSK & MFSK |
| D. | None of the mentioned |
| Answer» C. MPSK & MFSK | |
| 44. |
In a delta modulation system, granular noise occurs when the |
| A. | Modulating signal increases rapidly |
| B. | Pulse rate decreases |
| C. | Pulse amplitude decreases |
| D. | Modulating signal remains constant |
| Answer» E. | |
| 45. |
For more than two quantization level, _______ is used. |
| A. | Hard decision |
| B. | Soft decision |
| C. | Hard & Soft decision |
| D. | None of the mentioned |
| Answer» C. Hard & Soft decision | |
| 46. |
Space division has dedicated |
| A. | Paths |
| B. | Time slots |
| C. | Paths & Time slots |
| D. | None of the mentioned |
| Answer» B. Time slots | |
| 47. |
Which has the maximum power efficiency? |
| A. | Class A |
| B. | Class B |
| C. | Class C |
| D. | Class AB |
| Answer» D. Class AB | |
| 48. |
The IF transmission bandwidth of MFSK is |
| A. | M/T |
| B. | T/M |
| C. | 2M/T |
| D. | M/2 |
| Answer» B. T/M | |
| 49. |
In which technique spot beam antennas are used to point the radio signals in different directions? |
| A. | Code division |
| B. | Space division |
| C. | Frequency division |
| D. | None of the mentioned |
| Answer» C. Frequency division | |
| 50. |
Which modulation is spectrally more efficient? |
| A. | BPSK |
| B. | MSK |
| C. | QPSK |
| D. | OQPSK |
| Answer» C. QPSK | |