Difficulty: Easy
Correct Answer: Correct
Explanation:
Introduction / Context:Parity circuits are standard for low-cost error detection. A parity generator produces a parity bit from data, whereas a parity checker compares received data with the associated parity bit and flags mismatches. For 4-bit data words, a checker must consider all four data inputs plus the received parity input.
Given Data / Assumptions:
Concept / Approach:The same XOR building blocks used to generate parity are used to check parity. A checker XORs all five inputs. For even parity, a correct word yields 0; for odd parity, conventions vary (you may invert the result), but the single output still serves as the error indicator. Thus, the structural similarity and the five-input requirement are accurate.
Step-by-Step Solution:
Form the XOR of D3, D2, D1, D0 to generate parity in a generator.In a checker, XOR D3, D2, D1, D0, and the received parity P.If the result equals 0 for even parity (or 1 for odd, depending on convention), no error; otherwise, assert error.Verification / Alternative check:Test a valid even parity case: data 1011 has three ones; parity P = 1 to make total 4. XOR(1,0,1,1,1) = 0 → no error. Flip one bit and observe nonzero result → error.
Why Other Options Are Wrong:
Incorrect: Ignores the five-input requirement for checking.Only true for odd parity: Structure does not depend on parity type; only interpretation changes.Not enough information: The definition is standard and sufficient.Common Pitfalls:Confusing generator and checker roles; misinterpreting checker output polarity; forgetting that the checker consumes both data and parity.
Final Answer:Correct
Discussion & Comments