MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 86 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. |
Separating the symbols makes the channel memory-less. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2. |
Which has a limited resolution? |
| A. | Hard decision decoder |
| B. | Soft decision decoder |
| C. | Hard & Soft decision decoder |
| D. | None of the mentioned |
| Answer» C. Hard & Soft decision decoder | |
| 3. |
Transorthogonal code is obtained by |
| A. | Deleting last digit of each orthogonal codeword |
| B. | Deleting first digit of each orthogonal codeword |
| C. | Doubling each digit of orthogonal codeword |
| D. | Taking negative of each digit of orthogonal codeword |
| Answer» C. Doubling each digit of orthogonal codeword | |
| 4. |
A primitive element are those which yield ______ when raised to higher order exponents. |
| A. | All zero elements |
| B. | Non zero elements |
| C. | Unity elements |
| D. | None of the mentioned |
| Answer» C. Unity elements | |
| 5. |
Nyquist frequency is given by |
| A. | fs |
| B. | 2fs |
| C. | fs/2 |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 6. |
For better efficiency and simplicity, n should be |
| A. | Maximum |
| B. | Minimum |
| C. | Zero |
| D. | Infinity |
| Answer» C. Zero | |
| 7. |
In symmetric key cryptosystem, who knows the key? |
| A. | Sender |
| B. | Receiver |
| C. | Sender & Receiver |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 8. |
A feedback decoder makes hard decision. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 9. |
In a real time communication system addition of redundant bits leads to |
| A. | More bandwidth requirement |
| B. | Faster rate of transmission |
| C. | More bandwidth requirement & Faster rate of transmission |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 10. |
Sampling can be done for functions varying in |
| A. | Space |
| B. | Time |
| C. | Space & Time |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 11. |
Which is more efficient method? |
| A. | Encoding each symbol of a block |
| B. | Encoding block of symbols |
| C. | Encoding each symbol of a block & Encoding block of symbols |
| D. | None of the mentioned |
| Answer» C. Encoding each symbol of a block & Encoding block of symbols | |
| 12. |
Which has better minimum distance? |
| A. | Check sum |
| B. | Cyclic redundancy check |
| C. | Check sum & Cyclic redundancy check |
| D. | None of the mentioned |
| Answer» C. Check sum & Cyclic redundancy check | |
| 13. |
Reconstruction of continuous signals is done using |
| A. | Decimation algorithm |
| B. | Interpolation algorithm |
| C. | Decimation & Interpolation algorithm |
| D. | None of the mentioned |
| Answer» C. Decimation & Interpolation algorithm | |
| 14. |
The inter leaver connected between the two decoders is used to |
| A. | Remove error bursts |
| B. | Scatter error bursts |
| C. | Add error bursts |
| D. | None of the mentioned |
| Answer» C. Add error bursts | |
| 15. |
Coding gain is defined as |
| A. | Reduction in Eb/N0 |
| B. | Increase in Eb/N0 |
| C. | Same as Eb/N0 |
| D. | None of the mentioned |
| Answer» B. Increase in Eb/N0 | |
| 16. |
The look ahead length L is given by |
| A. | m+1 |
| B. | m-1 |
| C. | (m+1)/2 |
| D. | 1-m |
| Answer» B. m-1 | |
| 17. |
R-S codes have |
| A. | High code rate |
| B. | Low redundancy |
| C. | High code rate & Low redundancy |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 18. |
Reed Solomon codes are |
| A. | Non binary |
| B. | Cyclic |
| C. | Non binary & Cyclic |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 19. |
Oversampling can completely eliminate |
| A. | Aperture error |
| B. | Non linearity |
| C. | Quantization error |
| D. | All of the mentioned |
| Answer» B. Non linearity | |
| 20. |
A rate distortion function is a |
| A. | Concave function |
| B. | Convex function |
| C. | Increasing function |
| D. | None of the mentioned |
| Answer» C. Increasing function | |
| 21. |
Hamming distance can be given by the number of elements in which |
| A. | They are same |
| B. | They differ |
| C. | Which are non zero |
| D. | None of the mentioned |
| Answer» C. Which are non zero | |
| 22. |
CRC uses |
| A. | Multiplication |
| B. | Binary division |
| C. | Multiplication & Binary division |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 23. |
Block length is the _____________ in the code word. |
| A. | Number of elements |
| B. | Distance between elements |
| C. | Number of parity bits |
| D. | None of the mentioned |
| Answer» B. Distance between elements | |
| 24. |
Which are uniquely decodable codes? |
| A. | Fixed length codes |
| B. | Variable length codes |
| C. | Fixed & Variable length codes |
| D. | None of the mentioned |
| Answer» B. Variable length codes | |
| 25. |
Components used for generation of turbo codes are |
| A. | Inter leavers |
| B. | Punching pattern |
| C. | Inter leavers & Punching pattern |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 26. |
On increasing L |
| A. | Coding gain increases |
| B. | Complexity increases |
| C. | Coding gain & Complexity increases |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 27. |
Which factors are measured using the units of lines per picture height? |
| A. | Resolution |
| B. | Sampling rate |
| C. | Resolution & Sampling rate |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 28. |
A catastrophic error is an event whereby ______ number of code symbol error causes _______ number of decoded data error bits. |
| A. | Finite, finite |
| B. | Finite, infinite |
| C. | Infinite, finite |
| D. | Infinite, infinite |
| Answer» C. Infinite, finite | |
| 29. |
Sampling can be used in |
| A. | Audio |
| B. | Speech |
| C. | Video |
| D. | All of the mentioned |
| Answer» E. | |
| 30. |
The rate of a block code is the ration of |
| A. | Block length to message length |
| B. | Message length to block length |
| C. | Message weight to block length |
| D. | None of the mentioned |
| Answer» C. Message weight to block length | |
| 31. |
The minimum end to end delay in block interleaving is |
| A. | 2MN+2M+2 |
| B. | 2MN-2M+2 |
| C. | 2MN-2M-2 |
| D. | 2MN+2M-2 |
| Answer» C. 2MN-2M-2 | |
| 32. |
Which is used to protect privacy of the information? |
| A. | Compression coding |
| B. | Source coding |
| C. | Cipher coding |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 33. |
The probability of message error is written as |
| A. | Block error |
| B. | Word error |
| C. | Block & Word error |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 34. |
The capacity per cell is ______ Eb/N0. |
| A. | Directly proportional |
| B. | Inversely proportional |
| C. | Double the |
| D. | Half the |
| Answer» C. Double the | |
| 35. |
Lempel-Ziv algorithm is |
| A. | Variable to fixed length algorithm |
| B. | Fixed to variable length algorithm |
| C. | Fixed to fixed length algorithm |
| D. | Variable to variable length algorithm |
| Answer» B. Fixed to variable length algorithm | |
| 36. |
Sampling of simultaneously two different but related wave-forms is called as |
| A. | Over sampling |
| B. | Complex sampling |
| C. | Inter sampling |
| D. | None of the mentioned |
| Answer» C. Inter sampling | |
| 37. |
The smaller the cross correlation, the ______ is the distance between the signal vectors. |
| A. | More |
| B. | Less |
| C. | Double |
| D. | Half |
| Answer» B. Less | |
| 38. |
In maximum likelihood detector the error probability is |
| A. | Maximum |
| B. | Minimum |
| C. | Zero |
| D. | None of the mentioned |
| Answer» C. Zero | |
| 39. |
Example for convolution encoder state diagram is |
| A. | Tree diagram |
| B. | Trellis diagram |
| C. | Tree & Trellis diagram |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 40. |
If the inversion was performed correctly, then the multiplication of the original matrix with the inverted matrix should yield identity matrix. This is known as |
| A. | Identity theorem |
| B. | Safety theorem |
| C. | Multiplication theorem |
| D. | Inversion theorem |
| Answer» C. Multiplication theorem | |
| 41. |
Soft decision results in |
| A. | Increase in complexity |
| B. | Decrease in storage |
| C. | Increase in complexity & Decrease in storage |
| D. | None of the mentioned |
| Answer» B. Decrease in storage | |
| 42. |
Which needs more check bits? |
| A. | Error correction |
| B. | Error detection |
| C. | Error correction & detection |
| D. | None of the mentioned |
| Answer» B. Error detection | |
| 43. |
Turbo codes are |
| A. | Forward error correction codes |
| B. | Backward error correction codes |
| C. | Error detection codes |
| D. | None of the mentioned |
| Answer» B. Backward error correction codes | |
| 44. |
Error detecting capability is given as |
| A. | Dmin + 1 |
| B. | Dmin -1 |
| C. | Dmin |
| D. | Dmin/2 |
| Answer» C. Dmin | |
| 45. |
What is the bit depth used for audio recording? |
| A. | 8 bit |
| B. | 16 bit |
| C. | 24 bit |
| D. | All of the mentioned |
| Answer» E. | |
| 46. |
Biorthogonal codes needs ________ bandwidth as orthogonal codes. |
| A. | Equal |
| B. | Double |
| C. | Half |
| D. | Triple |
| Answer» D. Triple | |
| 47. |
A code should be selected such that it should |
| A. | Not have catastrophic error propagation |
| B. | Have minimum free distance |
| C. | All of the mentioned |
| D. | None of the mentioned |
| Answer» B. Have minimum free distance | |
| 48. |
Noise which can affect sampling are |
| A. | Thermal sensor noise |
| B. | Analog circuit noise |
| C. | Thermal sensor & Analog circuit noise |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 49. |
Which code requires minimum Eb/N0? |
| A. | Orthogonal |
| B. | Biorthogonal |
| C. | Simplex |
| D. | All of the mentioned |
| Answer» D. All of the mentioned | |
| 50. |
When X and Y are statistically independent, then I (x,y) is |
| A. | 1 |
| B. | 0 |
| C. | Ln 2 |
| D. | Cannot be determined |
| Answer» C. Ln 2 | |