Digital logic levels: “The voltage levels representing binary 0 and binary 1 in a digital system are nearly equal in value.” Evaluate this statement.

Introduction / Context:
Digital systems rely on distinct voltage windows to represent logic 0 and logic 1 robustly in the presence of noise. This question checks understanding of logic-level separation and noise margins.

Given Data / Assumptions:

• Standard logic families (TTL, CMOS) define VIH/VIL thresholds.
• “Nearly equal” would imply minimal separation between the two logic states.
• Noise margin must be adequate for reliable switching.

Concept / Approach:
Logic families specify valid ranges: for 5 V CMOS, for example, logic 0 is near 0 V (below VIL max) and logic 1 is near VDD (above VIH min). The gap between these windows forms noise margins, ensuring immunity to small disturbances. If the levels were nearly equal, the system would be intolerant to noise and indeterminate.

Step-by-Step Solution:

Verification / Alternative check:
Consult family datasheets; VIH and VIL differ by a significant fraction of supply, leaving noise margins NMH and NML for reliable operation.

Why Other Options Are Wrong:
Correct: would suggest no separation and unreliable operation, which is not how digital systems are defined.

Common Pitfalls:
Confusing “nearly rail-to-rail” with “nearly equal;” the former means outputs approach the supply rails, not that 0 and 1 are close to each other.

Final Answer:
Incorrect