Difficulty: Easy
Correct Answer: XOR gates
Explanation:
Introduction / Context: Gray code differs from binary by ensuring only one bit changes between consecutive values. Converters between Gray and binary are standard textbook circuits, and their structure hinges on a particular logic function applied cumulatively across bits.
Given Data / Assumptions:
Concept / Approach: The defining operation of these conversions is XOR (exclusive-OR). For Gray→binary: b[n] = g[n], and for each i from n-1 down to 0, b[i] = b[i+1] XOR g[i]. The cumulative XOR chain ensures that each binary bit correctly reflects the parity of the Gray prefix as required.
Step-by-Step Solution:
Start with MSB: b[n] = g[n].For next bit: b[n-1] = b[n] XOR g[n-1].Repeat down to LSB using XOR chaining.Binary-to-Gray uses XOR of adjacent binary bits: g[i] = b[i+1] XOR b[i].Verification / Alternative check:
Build a 4-bit converter and truth-table-check conversions both directions; XOR mapping will match expected sequences.Why Other Options Are Wrong:
XNOR gates: Would invert the parity relationship and produce incorrect mapping without extra inversions.AND / OR gates: Do not implement the required parity (mod-2 sum) relationship.Common Pitfalls:
Miswiring the XOR chain direction (using Gray instead of the previous binary bit).Forgetting that the MSB is copied directly.Final Answer:
XOR gates
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