MCQOPTIONS
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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.
| 51. |
Entropy of a random variable is |
| A. | 0 |
| B. | 1 |
| C. | Infinite |
| D. | Cannot be determined |
| Answer» D. Cannot be determined | |
| 52. |
Some various types of distortion are |
| A. | Jitter |
| B. | Noise |
| C. | Aperture error |
| D. | All of the mentioned |
| Answer» E. | |
| 53. |
Interpolation is a method of |
| A. | Interrelating |
| B. | Estimating |
| C. | Integrating |
| D. | Combining |
| Answer» C. Integrating | |
| 54. |
The number of errors that can be corrected without erasure information is |
| A. | Dmin+1 |
| B. | Dmin - 1 |
| C. | (Dmin+1)/2 |
| D. | (Dmin - 1)/2 |
| Answer» E. | |
| 55. |
A concatenated code has |
| A. | Low error rate |
| B. | High complexity |
| C. | Low error rate & High complexity |
| D. | None of the mentioned |
| Answer» B. High complexity | |
| 56. |
The self information of random variable is |
| A. | 0 |
| B. | 1 |
| C. | Infinite |
| D. | Cannot be determined |
| Answer» D. Cannot be determined | |
| 57. |
A concatenated code uses |
| A. | One level of coding |
| B. | Two levels of coding |
| C. | Three levels of coding |
| D. | None of the mentioned |
| Answer» C. Three levels of coding | |
| 58. |
Which gets less affected by noise? |
| A. | Error correction |
| B. | Error detection |
| C. | Error correction & detection |
| D. | None of the mentioned |
| Answer» C. Error correction & detection | |
| 59. |
The minimum distance for Reed Solomon code is given by |
| A. | n+k+1 |
| B. | n-k+1 |
| C. | 1-n-k |
| D. | 1+n-k |
| Answer» C. 1-n-k | |
| 60. |
Which factor is desirable? |
| A. | Minimum correlation |
| B. | Maximum correlation |
| C. | Maximum distance |
| D. | None of the mentioned |
| Answer» C. Maximum distance | |
| 61. |
Interpolation means |
| A. | Adding new data points |
| B. | Only aligning old data points |
| C. | Only removing old data points |
| D. | None of the mentioned |
| Answer» B. Only aligning old data points | |
| 62. |
Code strength is characterized by its |
| A. | Minimum distance |
| B. | Maximum distance |
| C. | Code weight |
| D. | Code size |
| Answer» B. Maximum distance | |
| 63. |
Digital signals are easy for |
| A. | Storage |
| B. | Handling |
| C. | Time dilation |
| D. | All of the mentioned |
| Answer» E. | |
| 64. |
Which parameter is used in soft decision algorithm? |
| A. | Euclidean distance |
| B. | Euclidean distance squared |
| C. | Euclidean distance & distance squared |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 65. |
In non orthogonal signalling as k increases there is |
| A. | Degraded error performance |
| B. | Improved bandwidth efficiency |
| C. | Increase in required Eb/N0 |
| D. | All of the mentioned |
| Answer» E. | |
| 66. |
The method used for representing convolution encoder are |
| A. | Connection pictorial |
| B. | State diagram |
| C. | Tree diagram |
| D. | All of the mentioned |
| Answer» E. | |
| 67. |
Greater the redundancy greater will be the error correcting capability. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 68. |
The k-bit message forms ____ distinct messages which is referred to as k-tuples. |
| A. | 2k |
| B. | K2 |
| C. | 2k |
| D. | 21/k |
| Answer» D. 21/k | |
| 69. |
Decoders are connected in series. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 70. |
Which are forward error correcting codes? |
| A. | Block codes |
| B. | Convolutional codes |
| C. | Block & Convolutional codes |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 71. |
If the quantization level of a demodulator output is ________ then it is called as soft decision decoding. |
| A. | Equal to 2 |
| B. | More than 2 |
| C. | Less than 2 |
| D. | None of the mentioned |
| Answer» C. Less than 2 | |
| 72. |
The performance of non binary concatenated code depends on |
| A. | Bit errors |
| B. | Symbols errors |
| C. | Bit & Symbols errors |
| D. | None of the mentioned |
| Answer» C. Bit & Symbols errors | |
| 73. |
Which is more complex? |
| A. | Encoding |
| B. | Decoding |
| C. | Encoding & Decoding |
| D. | None of the mentioned |
| Answer» C. Encoding & Decoding | |
| 74. |
The distance between two code-words is equal to the _____ of the third code-word which is the sum of the first two code-words. |
| A. | Size |
| B. | Weight |
| C. | Minimum distance |
| D. | None of the mentioned |
| Answer» C. Minimum distance | |
| 75. |
In maximum likelihood decoding technique, the likelihood function compares the |
| A. | Joint probabilities |
| B. | Individual probabilities |
| C. | Conditional probabilities |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 76. |
Which distance is related to the error correcting capability of the code? |
| A. | Maximum distance |
| B. | Minimum distance |
| C. | Maximum & Minimum distance |
| D. | None of the mentioned |
| Answer» C. Maximum & Minimum distance | |
| 77. |
A code is a mapping from |
| A. | Binary sequence to dicrete set of symbols |
| B. | Discrete set of symbols to binary sequence |
| C. | All of the mentioned |
| D. | None of the mentioned |
| Answer» C. All of the mentioned | |
| 78. |
In soft decision approach what does -127 mean? |
| A. | Certainly one |
| B. | Certainly zero |
| C. | Very likely zero |
| D. | Very likely one |
| Answer» C. Very likely zero | |
| 79. |
In trellis diagram, the number of nodes ______ at successive branching. |
| A. | Increases by 1 |
| B. | Doubles |
| C. | Triples |
| D. | None of the mentioned |
| Answer» C. Triples | |
| 80. |
For a binary code, the maximum number of possible sequence made up of L branch words is |
| A. | L2 |
| B. | 2L |
| C. | 2L |
| D. | L/2 |
| Answer» C. 2L | |
| 81. |
Linear codes are used for |
| A. | Forward error correction |
| B. | Backward error correction |
| C. | Forward error detection |
| D. | Backward error detection |
| Answer» B. Backward error correction | |
| 82. |
The error correcting capability of a code scheme increases as the |
| A. | Number of channel symbols per information bit increases |
| B. | Bandwidth increases |
| C. | Information per bit increases |
| D. | All of the mentioned |
| Answer» E. | |
| 83. |
Which operates on continuous stream of data? |
| A. | Block codes |
| B. | Convolutional codes |
| C. | Block & Convolutional codes |
| D. | None of the mentioned |
| Answer» C. Block & Convolutional codes | |
| 84. |
Which codes perform better? |
| A. | Orthogonal |
| B. | Biorthogonal |
| C. | Orthogonal & Biorthogonal |
| D. | None of the mentioned |
| Answer» C. Orthogonal & Biorthogonal | |
| 85. |
Which needs re-sending of signal? |
| A. | Error correction |
| B. | Error detection |
| C. | Error correction & detection |
| D. | None of the mentioned |
| Answer» C. Error correction & detection | |
| 86. |
The minimum distance Dmin can also be given as |
| A. | Dmin >= α + β + 1 |
| B. | Dmin <= α + β + 1 |
| C. | Dmin >= α + β - 1 |
| D. | Dmin <= α + β + 1 |
| Answer» B. Dmin <= α + β + 1 | |