McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Electrical Engineering .
| 1. |
In uniform quantization process |
| A. | the step size remains same |
| B. | step size varies according to the values of the input signal |
| C. | the quantizer has linear characteristics |
| D. | both a and c are correct |
| Answer» D. both a and c are correct | |
| 2. |
The process of converting the analog sample into discrete form is called |
| A. | modulation |
| B. | multiplexing |
| C. | quantization |
| D. | sampling |
| Answer» C. quantization | |
| 3. |
The characteristics of compressor in μ-law companding are |
| A. | continuous in nature |
| B. | logarithmic in nature |
| C. | linear in nature |
| D. | discrete in nature |
| Answer» A. continuous in nature | |
| 4. |
The modulation techniques used to convert analog signal into digital signal are |
| A. | pulse code modulation |
| B. | delta modulation |
| C. | adaptive delta modulation |
| D. | all of the above |
| Answer» D. all of the above | |
| 5. |
The sequence of operations in which PCM is done is |
| A. | sampling, quantizing, encoding |
| B. | quantizing, encoding, sampling |
| C. | quantizing, sampling, encoding |
| D. | none of the above |
| Answer» A. sampling, quantizing, encoding | |
| 6. |
In PCM, the parameter varied in accordance with the amplitude of the modulating signal is |
| A. | amplitude |
| B. | frequency |
| C. | phase |
| D. | none of the above |
| Answer» D. none of the above | |
| 7. |
One of the disadvantages of PCM is |
| A. | it requires large bandwidth |
| B. | very high noise |
| C. | cannot be decoded easily |
| D. | all of the above |
| Answer» A. it requires large bandwidth | |
| 8. |
The expression for bandwidth BW of a PCM system, where v is the number of bits per sample and fm is the modulating frequency, is given by |
| A. | bw ≥ vfm |
| B. | bw ≤ vfm |
| C. | bw ≥ 2 vfm |
| D. | bw ≥ 1/2 vfm |
| Answer» A. bw ≥ vfm | |
| 9. |
The error probability of a PCM is |
| A. | calculated using noise and inter symbol interference |
| B. | gaussian noise + error component due to inter symbol interference |
| C. | calculated using power spectral density |
| D. | all of the above |
| Answer» D. all of the above | |
| 10. |
In Delta modulation, |
| A. | one bit per sample is transmitted |
| B. | all the coded bits used for sampling are transmitted |
| C. | the step size is fixed |
| D. | both a and c are correct |
| Answer» D. both a and c are correct | |
| 11. |
In digital transmission, the modulation technique that requires minimum bandwidth is |
| A. | delta modulation |
| B. | pcm |
| C. | dpcm |
| D. | pam |
| Answer» A. delta modulation | |
| 12. |
In Delta Modulation, the bit rate is |
| A. | n times the sampling frequency |
| B. | n times the modulating frequency |
| C. | n times the nyquist criteria |
| D. | none of the above |
| Answer» A. n times the sampling frequency | |
| 13. |
In Differential Pulse Code Modulation techniques, the decoding is performed by |
| A. | accumulator |
| B. | sampler |
| C. | pll |
| D. | quantizer |
| Answer» A. accumulator | |
| 14. |
DPCM suffers from |
| A. | slope over load distortion |
| B. | quantization noise |
| C. | both a & b |
| D. | none of the above |
| Answer» C. both a & b | |
| 15. |
The noise that affects PCM |
| A. | transmission noise |
| B. | quantizing noise |
| C. | transit noise |
| D. | both a and b are correct |
| Answer» D. both a and b are correct | |
| 16. |
The factors that cause quantizing error in delta modulation are |
| A. | slope overload distortion |
| B. | granular noise |
| C. | white noise |
| D. | both a and b are correct |
| Answer» D. both a and b are correct | |
| 17. |
Granular noise occurs when |
| A. | step size is too small |
| B. | step size is too large |
| C. | there is interference from the adjacent channel |
| D. | bandwidth is too large |
| Answer» B. step size is too large | |
| 18. |
The crest factor of a waveform is given as – |
| A. | 2peak value/ rms value |
| B. | rms value / peak value |
| C. | peak value/ rms value |
| D. | peak value/ 2rms value |
| Answer» C. peak value/ rms value | |
| 19. |
The digital modulation technique in which the step size is varied according to the variation in the slope of the input is called |
| A. | delta modulation |
| B. | pcm |
| C. | adaptive delta modulation |
| D. | pam |
| Answer» C. adaptive delta modulation | |
| 20. |
The digital modulation scheme in which the step size is not fixed is |
| A. | delta modulation |
| B. | adaptive delta modulation |
| C. | dpcm |
| D. | pcm |
| Answer» B. adaptive delta modulation | |
| 21. |
In Adaptive Delta Modulation, the slope error reduces and |
| A. | quantization error decreases |
| B. | quantization error increases |
| C. | quantization error remains same |
| D. | none of the above |
| Answer» B. quantization error increases | |
| 22. |
The number of voice channels that can be accommodated for transmission in T1 carrier system is |
| A. | 24 |
| B. | 32 |
| C. | 56 |
| D. | 64 |
| Answer» A. 24 | |
| 23. |
The maximum data transmission rate in T1 carrier system is |
| A. | 2.6 megabits per second |
| B. | 1000 megabits per second |
| C. | 1.544 megabits per second |
| D. | 5.6 megabits per second |
| Answer» C. 1.544 megabits per second | |
| 24. |
T1 carrier system is used |
| A. | for pcm voice transmission |
| B. | for delta modulation |
| C. | for frequency modulated signals |
| D. | none of the above |
| Answer» A. for pcm voice transmission | |
| 25. |
Matched filter may be optimally used only for |
| A. | gaussian noise |
| B. | transit time noise |
| C. | flicker |
| D. | all of the above |
| Answer» A. gaussian noise | |
| 26. |
Matched filters may be used |
| A. | to estimate the frequency of the received signal |
| B. | in parameter estimation problems |
| C. | to estimate the distance of the object |
| D. | all of the above |
| Answer» D. all of the above | |
| 27. |
The process of coding multiplexer output into electrical pulses or waveforms for transmission is called |
| A. | line coding |
| B. | amplitude modulation |
| C. | fsk |
| D. | filtering |
| Answer» A. line coding | |
| 28. |
For a line code, the transmission bandwidth must be |
| A. | maximum possible |
| B. | as small as possible |
| C. | depends on the signal |
| D. | none of the above |
| Answer» B. as small as possible | |
| 29. |
Regenerative repeaters are used for |
| A. | eliminating noise |
| B. | reconstruction of signals |
| C. | transmission over long distances |
| D. | all of the above |
| Answer» D. all of the above | |
| 30. |
Scrambling of data is |
| A. | removing long strings of 1’s and 0’s |
| B. | exchanging of data |
| C. | transmission of digital data |
| D. | all of the above |
| Answer» A. removing long strings of 1’s and 0’s | |
| 31. |
In polar RZ format for coding, symbol ‘0’ is represented by |
| A. | zero voltage |
| B. | negative voltage |
| C. | pulse is transmitted for half the duration |
| D. | both b and c are correct |
| Answer» D. both b and c are correct | |
| 32. |
Polar coding is a technique in which |
| A. | 1 is transmitted by a positive pulse and 0 is transmitted by negative pulse |
| B. | 1 is transmitted by a positive pulse and 0 is transmitted by zero volts |
| C. | both a & b |
| D. | none of the above |
| Answer» A. 1 is transmitted by a positive pulse and 0 is transmitted by negative pulse | |
| 33. |
The polarities in NRZ format use |
| A. | complete pulse duration |
| B. | half duration |
| C. | both positive as well as negative value |
| D. | each pulse is used for twice the duration |
| Answer» A. complete pulse duration | |
| 34. |
The format in which the positive half interval pulse is followed by a negative half interval pulse for transmission of ‘1’ is |
| A. | polar nrz format |
| B. | bipolar nrz format |
| C. | manchester format |
| D. | none of the above |
| Answer» C. manchester format | |
| 35. |
The maximum synchronizing capability in coding techniques is present in |
| A. | manchester format |
| B. | polar nrz |
| C. | polar rz |
| D. | polar quaternary nrz |
| Answer» A. manchester format | |
| 36. |
The advantage of using Manchester format of coding is |
| A. | power saving |
| B. | polarity sense at the receiver |
| C. | noise immunity |
| D. | none of the above |
| Answer» A. power saving | |
| 37. |
Alternate Mark Inversion (AMI) is also known as |
| A. | pseudo ternary coding |
| B. | manchester coding |
| C. | polar nrz format |
| D. | none of the above |
| Answer» A. pseudo ternary coding | |
| 38. |
In DPSK technique, the technique used to encode bits is |
| A. | ami |
| B. | differential code |
| C. | uni polar rz format |
| D. | manchester format |
| Answer» B. differential code | |
| 39. |
Overhead bits are |
| A. | framing and synchronizing bits |
| B. | data due to noise |
| C. | encoded bits |
| D. | none of the above |
| Answer» A. framing and synchronizing bits | |
| 40. |
ISI may be removed by using |
| A. | differential coding |
| B. | manchester coding |
| C. | polar nrz |
| D. | none of the above |
| Answer» A. differential coding | |
| 41. |
Timing jitter is |
| A. | change in amplitude |
| B. | change in frequency |
| C. | deviation in location of the pulses |
| D. | all of the above |
| Answer» C. deviation in location of the pulses | |
| 42. |
Probability density function defines |
| A. | amplitudes of random noise |
| B. | density of signal |
| C. | probability of error |
| D. | all of the above |
| Answer» A. amplitudes of random noise | |
| 43. |
Impulse noise is caused due to |
| A. | switching transients |
| B. | lightening strikes |
| C. | power line load switching |
| D. | all of the above |
| Answer» D. all of the above | |
| 44. |
In coherent detection of signals, |
| A. | local carrier is generated |
| B. | carrier of frequency and phase as same as transmitted carrier is generated |
| C. | the carrier is in synchronization with modulated carrier |
| D. | all of the above |
| Answer» D. all of the above | |
| 45. |
Synchronization of signals is done using |
| A. | pilot clock |
| B. | extracting timing information from the received signal |
| C. | transmitter and receiver connected to master timing source |
| D. | all of the above |
| Answer» D. all of the above | |
| 46. |
Orthogonality of two codes means |
| A. | the integrated product of two different code words is zero |
| B. | the integrated product of two different code words is one |
| C. | the integrated product of two same code words is zero |
| D. | none of the above |
| Answer» A. the integrated product of two different code words is zero | |
| 47. |
In Alternate Mark Inversion (AMI) is |
| A. | 0 is encoded as positive pulse and 1 is encoded as negative pulse |
| B. | 0 is encoded as no pulse and 1 is encoded as negative pulse |
| C. | 0 is encoded as negative pulse and 1 is encoded as positive pulse |
| D. | 0 is encoded as no pulse and 1 is encoded as positive or negative pulse |
| Answer» B. 0 is encoded as no pulse and 1 is encoded as negative pulse | |
| 48. |
Advantages of using AMI |
| A. | needs least power as due to opposite polarity |
| B. | prevents build-up of dc |
| C. | may be used for longer distance |
| D. | all of the above |
| Answer» D. all of the above | |
| 49. |
The interference caused by the adjacent pulses in digital transmission is called |
| A. | inter symbol interference |
| B. | white noise |
| C. | image frequency interference |
| D. | transit time noise |
| Answer» A. inter symbol interference | |
| 50. |
Eye pattern is |
| A. | is used to study isi |
| B. | may be seen on cro |
| C. | resembles the shape of human eye |
| D. | all of the above |
| Answer» D. all of the above | |
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