Flip-flop triggering style nomenclature: Pulse-triggered flip-flops are also commonly referred to as __________ flip-flops in standard digital design texts.
-
Alevel
-
Bedge
-
Cmaster-slave
-
Dpostponed
-
Emetastable
Answer
Correct Answer: level
Explanation
Introduction / Context:Digital storage elements may be categorized by how their control inputs cause state changes. Pulse-triggered devices respond over the duration of an enable (or clock) pulse, which corresponds to level sensitivity during that interval. This contrasts with edge-triggered devices that respond only at the instant of a transition.
Given Data / Assumptions:
- “Pulse-triggered” refers to devices that are transparent or responsive while a specified control level is present.
- We are using common textbook terminology.
Concept / Approach:Pulse-triggered flip-flops are functionally equivalent to level-sensitive devices because the effective action occurs while the control signal is at an active level (high-level or low-level, depending on design). Master–slave organization is one technique to mitigate race-around by using two level-sensitive stages in sequence; however, the term “pulse-triggered” itself maps to “level-sensitive,” not “edge-triggered.”
Step-by-Step Solution:
Identify the behavior: responds during a time window (the pulse).A window response equals level sensitivity during the active level.Therefore, the conventional label is “level” flip-flop (level-sensitive).Verification / Alternative check:Timing diagrams show that state may change for any input variation occurring while the enable level is active. Edge-triggered devices, by contrast, sample at a single instant, confirming the distinction and the naming convention.
Why Other Options Are Wrong:
- Edge: Opposite concept; acts at an instant.
- Master-slave: An implementation technique, not a trigger style name.
- Postponed/metastable: Not standard trigger-type nomenclature.
Common Pitfalls:Equating “pulse” with “edge”; forgetting that a pulse has duration that allows transparency/race without proper design precautions.
Final Answer:level