If the ASCII character H is sent but the ASCII character I is received at the destination, which type of transmission error has most likely occurred?
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Asingle-bit
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Bmultiple-bit
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Cburst
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Drecoverable
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ENone of the above
Answer
Correct Answer: single-bit
Explanation
Introduction:Error types are classified by how many bits flip and how those flips are distributed within a unit of data. Identifying the likely class of error from observed symbol changes is a common exam task and informs the choice of error-detecting/correcting codes.
Given Data / Assumptions:
- ASCII uppercase H (decimal 72) is sent.
- ASCII uppercase I (decimal 73) is received.
- We assume an 8-bit character with standard ASCII coding.
Concept / Approach:Convert the characters to binary: H = 0x48 = 01001000; I = 0x49 = 01001001. The two codewords differ by exactly one least significant bit. Therefore, the most parsimonious explanation is a single-bit error in transit. Multiple-bit or burst errors would typically change more than one bit position within the character.
Step-by-Step Solution:1) Write H in binary: 01001000.2) Write I in binary: 01001001.3) Compare bit by bit: only the last bit differs (0 → 1).4) Conclude: a single-bit error is indicated.
Verification / Alternative check:Compute Hamming distance between the two 8-bit codewords; distance = 1 confirms a single-bit flip.
Why Other Options Are Wrong:
- Multiple-bit: would change two or more positions.
- Burst: contiguous run of erroneous bits; not observed here.
- Recoverable: not a standard error type classification; recoverability depends on the code used.
- None of the above: invalid because single-bit fits exactly.
Common Pitfalls:Assuming character substitution implies many flipped bits; with ASCII adjacency, neighboring letters often differ by a single bit.
Final Answer:single-bit