Download to read offline
Uploaded byAsif Iqbal
Unit 5
This document contains a multiple choice quiz on digital communication topics including cyclic codes, block codes, linear codes, trellis coded modulation, source coding, channel coding, sampling, and digital image coding. There are 54 questions in total testing knowledge of concepts such as generator polynomials, feedback shift registers, coding rate, minimum distance, entropy coding, quantization error, sampling rate, and reconstruction of continuous signals from samples.
More Related Content
Unit 5
- 1. NEC 602 DigitalCommunication MCQ for unit 5 1. The cyclic codes are designed using a) Shift registers with feedback b) Shift registers without feedback c) Flipflops d) None of the mentioned 2. A cyclic code can be generated using a) Generator polynomial b) Generator matrix c) Both of the mentioned d) None of the mentioned 3. The feedback shift register circuit is called as a) Multiplying circuit b) Dividing circuit c) Feedback circuit d) Shifting circuit 4. In the dividing circuit, the parity polynomial is obtained by the a) Quotient b) Remainder c) Dividend d) Divisor 5. The received code contains error if the syndrome vector is a) Zero b) Non zero c) Infinity d) None of the mentioned 6. Block codes are generated using a) Generator polynomial b) Generator matrix c) Both of the mentioned d) None of the mentioned
- 2. 7. Extended go-laycode is formed by a) Adding overall parity bit to perfect go-lay code b) Ex-oaring overall parity bit with perfect go-lay code c) Ex-oaring each bit of go-lay code d) Dividing the overall parity bit with perfect go-lay code 8. 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 9. 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 10. Linear codes are used for a) Forward error correction b) Backward error correction c) Forward error detection d) Backward error detection 11. The k-bit message forms ____ distinct messages which is referred to as k-tuples. a) 2k b) K2 c) 2k d) 21/k 12. The sum of any two vectors in subset S is also in S. This is called as a) Addition property b) Subset property c) Closure property d) Similarity property 13. To avoid corruption during transmission, the code-word should be a) Near b) Far apart c) Both of the mentioned d) None of the mentioned 14. In a standard matrix set code-word there are _______ cosset. a) 2k b) 2n+k c) 2n-k d) 2n
- 3. 15. Syndrome iscalculated by a) HT/r b) rHT c) rH d) None of the mentioned 16. The _____ of the code-word is the number of non zero elements. a) Size b) Weight c) Distance d) Subspace 17. Some examples of linear codes a) Hamming code b) Reed-Solomon code c) Parity code d) All of the mentioned 18. Adding improvement to the signal subset choice by starting with the densest possible lattice for the space is called as a) Optimum signal constellation boundaries b) Higher density lattice structures c) Trellis coded modulation d) None of the mentioned 19. Choosing a closely packed signal subset from any regular lattice or array of candidate points is called as a) Optimum signal constellation boundaries b) Higher density lattice structures c) Trellis coded modulation d) None of the mentioned 20. Trellis coded modulation uses a) Non binary method b) Uses redundant bits c) No expansion of bandwidth d) All of the mentioned 21. In finite state machines, output is predicted using a) Past output b) Present input c) Both of the mentioned d) None of the mentioned 22. In TCM the signals are decoded using a) Soft decision decoders b) Hard decision decoders c) Both of the mentioned d) None of the mentioned
- 4. 23. Trellis codedmodulation scheme a) Has memory b) Is memory-less c) Needs more bandwidth d) None of the mentioned 24. In TCM channel capacity can be increased. a) True b) False 25. Transmission bandwidth depends on a) Rate of signalling b) Density of signal points c) Both of the mentioned d) None of the mentioned 26. Which determines the error performance in TCM? a) Reduced distance b) Free distance c) Bandwidth d) None of the mentioned 27. The TCM decoder uses a) Minimum likelihood detector b) Maximum likelihood detector c) Does not use redundant bits d) None of the mentioned 28. While recovering signal, which gets attenuated more? a) Low frequency component b) High frequency component c) Both of the mentioned d) None of the mentioned 29. Mutual information should be a) Positive b) Negative c) Both of the mentioned d) None of the mentioned 30. ASCII code is a a) Fixed length code b) Variable length code c) Both of the mentioned d) None of the mentioned 31. Which reduces the size of the data? a) Source coding b) Channel coding
- 5. c) Both ofthe mentioned d) None of the mentioned 32. In digital image coding which image must be smaller in size? a) Input image b) Output image c) Both of the mentioned d) None of the mentioned 33. Which coding method uses entropy coding? a) Lossless coding b) Lossy coding c) Both of the mentioned d) None of the mentioned 34. Which achieves greater compression? a) Lossless coding b) Lossy coding c) Both of the mentioned d) None of the mentioned 35. A code is a mapping from a) Binary sequence to dicrete set of symbols b) Discrete set of symbols to binary sequence c) Both of the mentioned d) None of the mentioned 36. Which are uniquely decodable codes? a) Fixed length codes b) Variable length codes c) Both of the mentioned d) None of the mentioned 37. A rate distortion function is a a) Concave function b) Convex function c) Increasing function d) None of the mentioned 38. 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 39. Code strength is characterized by its a) Minimum distance b) Maximum distance c) Code weight
- 6. d) Code size 40.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 41. Error detecting capability is given as a) Dmin + 1 b) Dmin -1 c) Dmin d) Dmin/2 42. 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 43. 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 44. For better efficiency and simplicity, n should be a) Maximum b) Minimum c) Zero d) Infinity 45. Nyquist frequency is given by a) fs b) 2fs c) fs/2 d) None of the mentioned 46. Some various types of distortion are a) Jitter b) Noise c) Aperture error d) All of the mentioned 47. Noise which can affect sampling are a) Thermal sensor noise b) Analog circuit noise
- 7. c) Both ofthe mentioned d) None of the mentioned 48. Oversampling can completely eliminate a) Aperture error b) Non linearity c) Quantization error d) All of the mentioned 49. Sampling can be used in a) Audio b) Speech c) Video d) All of the mentioned 50. What is the bit depth used for audio recording? a) 8 bit b) 16 bit c) 24 bit d) All of the mentioned 51. Which factors are measured using the units of lines per picture height? a) Resolution b) Sampling rate c) Both of the mentioned d) None of the mentioned 52. 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 53. Sampling can be done for functions varying in a) Space b) Time c) Both of the mentioned d) None of the mentioned 54. Reconstruction of continuous signals is done using a) Decimation algorithm b) Interpolation algorithm c) Both of the mentioned d) None of the mentioned