Definition of a glitch in digital circuits: Assess the statement: “A glitch is a short, unintended pulse that can lead to an undesired result in a digital circuit due to logic hazards or timing.”

Difficulty: Easy

Correct Answer: Correct

Explanation:


Introduction / Context:
Glitches are abrupt, brief pulses appearing on digital signals when logic paths with different delays momentarily disagree. Even if the correct steady-state value is eventually reached, the transient pulse can trigger downstream elements, causing incorrect counts, spurious writes, or false interrupts. This question probes your understanding of what a glitch is and why it matters.



Given Data / Assumptions:

  • Digital gates have finite propagation delays.
  • Multiple reconverging paths can create hazards (static or dynamic).
  • Sequential circuits may respond to brief pulses if timing permits.


Concept / Approach:
When inputs transition, unequal path delays can produce a temporary output level that does not match the final logic evaluation. This momentary excursion is a glitch. Designers mitigate glitches by using synchronous sampling, hazard-free logic forms, proper gate balancing, or registering outputs before they drive sensitive destinations.



Step-by-Step Solution:

Recognize that hazards arise on reconvergent fanouts.Understand that unequal delays create brief pulses inconsistent with final logic.See that a flip-flop clock edge sampling a glitch may capture a wrong value.Therefore, a glitch is indeed a short undesired pulse that can cause errors.


Verification / Alternative check:
Waveform simulations show narrow spikes during input transitions; timing analysis identifies hazard conditions and recommends registering or re-timing.



Why Other Options Are Wrong:

Incorrect: Ignores the well-known definition of glitches.Only true for analog / only in asynchronous: Glitches occur in both asynchronous and synchronous systems; synchronous design merely reduces their impact via clocked boundaries.


Common Pitfalls:
Feeding combinational outputs directly into asynchronous controls; ignoring minimum pulse width specs of receiving circuits; assuming slow edges eliminate glitches.


Final Answer:
Correct

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