In this particular topic you have learned that Data can be corrupted during transmission. To address this issue some applications require that errors be detected and must be corrected. If you skip the summary visit Error Detection and Correction.
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Choose the letter of the best answer in each questions.
1. Checksums use _________ arithmetic.
- A) one’s complement arithmetic
- B) two’s complement arithmetic
- C) either (a) or (b)
- D) none of the above
Answer: Option A
Solution:
2. The checksum of 1111 and 1111 is _________.
- A) 0000
- B) 1111
- C) 1110
- D) 0111
Answer: Option A
Solution:
3. In modulo-11 arithmetic, we use only the integers in the range ______, inclusive.
- A) 1 to 10
- B) 0 to 10
- C) 1 to 11
- D) none of the above
Answer: Option B
Solution:
4. In cyclic redundancy checking, the divisor is _______ the CRC.
- A) one bit less than
- B) one bit more than
- C) The same size as
- D) none of the above
Answer: Option B
Solution:
5. The ________ between two words is the number of differences between corresponding bits.
- A) Hamming rule
- B) Hamming code
- C) Hamming distance
- D) none of the above
Answer: Option C
Solution:
6. The _______ of a polynomial is the highest power in the polynomial.
- A) range
- B) power
- C) degree
- D) none of the above
Answer: Option C
Solution:
7. In modulo-2 arithmetic, __________ give the same results.
- A) addition and subtraction
- B) addition and multiplication
- C) addition and division
- D) none of the above
Answer: Option A
Solution:
8. In cyclic redundancy checking, what is the CRC?
- A) The quotient
- B) The dividend
- C) The divisor
- D) The remainder
Answer: Option D
Solution:
9. Which error detection method consists of just one redundant bit per data unit?
- A) CRC
- B) Checksum
- C) Simple parity check
- D) Two-dimensional parity check
Answer: Option C
Solution:
10. In _____ coding, we divide our message into blocks, each of k bits, called ___.
- A) block; blockwords
- B) block; datawords
- C) linear; datawords
- D) none of the above
Answer: Option B
Solution:
11. A _____ error means that two or more bits in the data unit have changed.
- A) burst
- B) double-bit
- C) single-bit
- D) none of the above
Answer: Option A
Solution:
12. Adding 1 and 1 in modulo-2 arithmetic results in _________.
- A) 0
- B) 1
- C) 2
- D) none of the above
Answer: Option A
Solution:
13. In ________ error correction, the receiver corrects errors without requesting retransmission.
- A) onward
- B) forward
- C) backward
- D) none of the above
Answer: Option B
Solution:
14. If the Hamming distance between a dataword and the corresponding codeword is three, there are _____ bits in error.
- A) 5
- B) 4
- C) 3
- D) none of the above
Answer: Option C
Solution:
15. A simple parity-check code can detect __________ errors.
- A) an odd-number of
- B) an even-number of
- C) two
- D) no errors
Answer: Option A
Solution:
16. The Hamming distance between equal codewords is _________.
- A) 0
- B) 1
- C) n
- D) none of the above
Answer: Option A
Solution:
17. In a linear block code, the _______ of any two valid codewords creates another valid codeword.
- A) ANDing
- B) XORing
- C) ORing
- D) none of the above
Answer: Option B
Solution:
18. In ________ error correction, the receiver asks the sender to send the data again.
- A) forward
- B) backward
- C) retransmission
- D) none of the above
Answer: Option C
Solution:
19. We can divide coding schemes into two broad categories: ________ and ______coding.
- A) linear; nonlinear
- B) block; convolution
- C) block; linear
- D) none of the above
Answer: Option B
Solution:
20. In modulo-2 arithmetic, we use only ______.
- A) 1 and 2
- B) 0 and 1
- C) 0 and 2
- D) none of the above
Answer: Option B
Solution:
21. To guarantee correction of up to 5 errors in all cases, the minimum Hamming distance in a block code must be ________.
- A) 11
- B) 6
- C) 5
- D) none of the above
Answer: Option A
Solution:
22. The _____of errors is more difficult than the ______.
- A) detection; correction
- B) correction; detection
- C) creation; correction
- D) creation; detection
Answer: Option B
Solution:
23. In block coding, if k = 2 and n = 3, we have _______ invalid codewords.
- A) 4
- B) 8
- C) 2
- D) none of the above
Answer: Option A
Solution:
24. The checksum of 0000 and 0000 is __________.
- A) 0000
- B) 1111
- C) 0111
- D) 1110
Answer: Option B
Solution:
25. In one’s complement arithmetic, if positive 7 is 0111, then negative 7 is ________.
- A) 1101
- B) 1000
- C) 1111
- D) none of the above
Answer: Option B
Solution:
26. In block coding, if n = 5, the maximum Hamming distance between two codewords is ________.
- A) 5
- B) 3
- C) 2
- D) none of the above
Answer: Option A
Solution:
27. Which error detection method uses one’s complement arithmetic?
- A) Checksum
- B) CRC
- C) Simple parity check
- D) Two-dimensional parity check
Answer: Option A
Solution:
28. The divisor in a cyclic code is normally called the _________.
- A) redundancy
- B) degree
- C) generator
- D) none of the above
Answer: Option C
Solution:
29. In modulo-2 arithmetic, we use the ______ operation for both addition and subtraction.
- A) OR
- B) XOR
- C) AND
- D) none of the above
Answer: Option B
Solution:
30. We add r redundant bits to each block to make the length n = k + r. The resulting n-bit blocks are called _________.
- A) codewords
- B) datawords
- C) blockwords
- D) none of the above
Answer: Option A
Solution:
31. To guarantee the detection of up to 5 errors in all cases, the minimum Hamming distance in a block code must be _______.
- A) 11
- B) 5
- C) 6
- D) none of the above
Answer: Option C
Solution:
32. A generator that contains a factor of ____ can detect all odd-numbered errors.
- A) x
- B) 1
- C) x + 1
- D) none of the above
Answer: Option C
Solution:
33. _______codes are special linear block codes with one extra property. If a codeword is rotated, the result is another codeword.
- A) Convolution
- B) Cyclic
- C) Non-linear
- D) none of the above
Answer: Option B
Solution:
34. The Hamming distance between 100 and 001 is ________.
- A) 0
- B) 1
- C) 2
- D) none of the above
Answer: Option C
Solution:
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Complete List of Chapter Quiz in Data Communications and Networking
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