Symbol interpretation — postponed output marking on flip-flop symbols: Some schematic symbol conventions show a special “postponed” mark at the output of a flip-flop. This annotation indicates that the output change is associated with a specific clock edge behavior. What does this postponed output symbol identify?

Difficulty: Medium

Correct Answer: trailing edge-triggered

Explanation:


Introduction / Context:
Logic-symbol annotations convey timing semantics without long notes. Bubbles, triangles, and auxiliary marks denote active polarities and edge sensitivities. A “postponed” marking at a flip-flop’s output is one such convention that indicates the output’s relationship to clock edges.



Given Data / Assumptions:

  • We refer to symbol conventions where outputs may be annotated to show when state changes appear.
  • Edge sense (leading vs. trailing) is the key attribute being identified.
  • Device family specifics may vary, but the core meaning is consistent: postponed output corresponds to a defined edge relation.


Concept / Approach:
Standard symbolism uses a triangle at the clock input to show edge triggering and a bubble to indicate inversion (e.g., negative-edge). Some libraries further annotate outputs to clarify that the visible change at Q is “postponed” to a particular edge (often the trailing edge in a master-slave implementation). This communicates that although internal storage may occur earlier, the observable output transition appears on the specified edge.



Step-by-Step Solution:

Recognize what the postponed mark conveys: an intentional delay/link to a particular clock edge.Differentiate from pulse-triggered: monostables/timers use pulses rather than stable edges for state capture.Conclude that the symbol identifies the output as trailing edge-triggered.


Verification / Alternative check:

Check design guides where master-slave behavior is illustrated: internal latching occurs first, but output “postpones” until the next (trailing) edge.


Why Other Options Are Wrong:

a D flip-flop / a J-K flip-flop: Type identification is not the purpose of the postponed mark.pulse triggered: Pulse-triggering is a different concept related to one-shots or dynamic transmission-gate structures, not specifically the postponed output marking.


Common Pitfalls:

Assuming every symbol set uses identical annotations; always check the legend for the drafting standard in use.Confusing input edge symbols (at the clock pin) with output annotations.


Final Answer:

trailing edge-triggered

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