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.
| 51. |
According to Parseval's theorem the energy spectral density curve is equal to? |
| A. | Area under magnitude of the signal |
| B. | Area under square of the magnitude of the signal |
| C. | Area under square root of magnitude of the signal |
| D. | None of the mentioned |
| Answer» C. Area under square root of magnitude of the signal | |
| 52. |
Autocorrelation is maximum at _______ |
| A. | Unity |
| B. | Origin |
| C. | Infinite point |
| D. | None of the mentioned |
| Answer» C. Infinite point | |
| 53. |
Ground wave communication occurs in |
| A. | Low frequency band |
| B. | Medium frequency band |
| C. | Low & Medium frequency band |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 54. |
The attenuation level in bounded power spectral density is |
| A. | 35 |
| B. | 50 |
| C. | 35 & 50 |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 55. |
Autocorrelation function of periodic signal is equal to _______ |
| A. | Energy of the signal |
| B. | Power of the signal |
| C. | Its area in frequency domain |
| D. | None of the mentioned |
| Answer» C. Its area in frequency domain | |
| 56. |
The point at which the output signal power has fallen to 0.707 of its peak value is called as _____ |
| A. | 3db point |
| B. | Half power point |
| C. | 3db & Half power point |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 57. |
Which noise is useful for dithering? |
| A. | White noise |
| B. | Pink noise |
| C. | Brown noise |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 58. |
Flicker noise is called as |
| A. | White noise |
| B. | Pink noise |
| C. | Brown noise |
| D. | None of the mentioned |
| Answer» C. Brown noise | |
| 59. |
Perform the bit stream partitioning and find the 8-ary waveform for the word 'THINK'. |
| A. | 1204443464 |
| B. | 4643444021 |
| C. | 1240443464 |
| D. | none of the mentioned |
| Answer» B. 4643444021 | |
| 60. |
Formatting is the process which includes |
| A. | Pulse code modulation |
| B. | Sampling |
| C. | Quantization |
| D. | All of the mentioned |
| Answer» E. | |
| 61. |
Find the 32-ary waveform for the word 'THINK'. |
| A. | 514172520 |
| B. | 202517415 |
| C. | 541172520 |
| D. | None of the mentioned |
| Answer» B. 202517415 | |
| 62. |
Matched filter is |
| A. | Linear |
| B. | Non linear |
| C. | Linear & Non linear |
| D. | None of the mentioned |
| Answer» B. Non linear | |
| 63. |
Which consists of less ISI? |
| A. | Nyquist filter |
| B. | Raised cosine filter |
| C. | Nyquist & Raised cosine filter |
| D. | None of the mentioned |
| Answer» C. Nyquist & Raised cosine filter | |
| 64. |
The basic transmission-reception system is a ______ system. |
| A. | Two block system |
| B. | Three block system |
| C. | Four block system |
| D. | None of the mentioned |
| Answer» C. Four block system | |
| 65. |
Matched filter technique is used to |
| A. | Increase SNR |
| B. | Decrease SNR |
| C. | SNR is not affected |
| D. | None of the mentioned |
| Answer» B. Decrease SNR | |
| 66. |
Constellation diagram is plotted in |
| A. | Constellation space |
| B. | Signal space |
| C. | Orthogonal space |
| D. | Boundary space |
| Answer» C. Orthogonal space | |
| 67. |
Which filter has maximum flatness? |
| A. | Chebyshev filter |
| B. | Butter-worth filter |
| C. | High pass filter |
| D. | Normalized filter |
| Answer» C. High pass filter | |
| 68. |
Find the periodicity of the following signal. x(t)=cos((2π/7)t)sin((3π/5)t) |
| A. | 30 |
| B. | 7 |
| C. | 35 |
| D. | 5/3 |
| Answer» D. 5/3 | |
| 69. |
Random things in a communication system are |
| A. | Timing offset |
| B. | Device frequency |
| C. | Attenuation |
| D. | All of the mentioned |
| Answer» E. | |
| 70. |
The information source of a digital communication system can be |
| A. | Packetized |
| B. | Continuous |
| C. | Packetized & Continuous |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 71. |
Satellite communication takes place in |
| A. | Ultra high frequency band |
| B. | Super high frequency band |
| C. | Ultra & Super high frequency band |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 72. |
The maximum likelihood function is |
| A. | Positive |
| B. | Negative |
| C. | Any of the mentioned |
| D. | None of the mentioned |
| Answer» B. Negative | |
| 73. |
Which can be used for periodic and non periodic? |
| A. | Fourier series |
| B. | Fourier transforms |
| C. | Fourier series & transforms |
| D. | None of the mentioned |
| Answer» C. Fourier series & transforms | |
| 74. |
Find the fundamental period of 1+sin^2 (3π/5)n. |
| A. | 10/3 |
| B. | 5 |
| C. | 3π/5 |
| D. | None of the mentioned |
| Answer» C. 3π/5 | |
| 75. |
Digital communication system can handle |
| A. | Analog signals |
| B. | 1D signals |
| C. | 2D signals |
| D. | All of the mentioned |
| Answer» E. | |
| 76. |
If operating frequency bands are higher ______ is available. |
| A. | Smaller bandwidth |
| B. | Larger bandwidth |
| C. | Smaller & Larger bandwidth |
| D. | Cannot be determined |
| Answer» C. Smaller & Larger bandwidth | |
| 77. |
The auto-correlation of white noise is |
| A. | A delta function |
| B. | A constant |
| C. | Gaussian |
| D. | None of the mentioned |
| Answer» B. A constant | |
| 78. |
A band-pass signal has |
| A. | DC component |
| B. | No DC component |
| C. | No side lobes |
| D. | Cannot be determined |
| Answer» C. No side lobes | |