D Flip-Flop Propagation Timing

D flip-flop propagation delay timing

A D flip-flop timing diagram compares the clock, reset, input data and registered Q output. Data changes are shown against a common clock, while Q changes after the applicable capture edge to make the propagation delay visible. The reset interval establishes a known starting state before normal operation. This drawing is useful in a classroom, design review or interface specification because it separates the data waveform from the state held by the register. For implementation work, add clock-enable behavior, asynchronous controls, setup and hold windows, and technology-specific delay values where needed. A timing diagram communicates the intended relationship between signals; it does not replace static timing analysis.

類型 時序圖標準 WaveDrom-compatible signal description引擎 schematex-timing更新時間 2026/9/24

需求

“Draw D flip-flop timing with an eight-cycle clock, reset high for two cycles then low, data changing every two cycles, and Q changing one cycle after the captured data.”

接著試試Add a clock-enable signal.Change reset to active low.

這張圖裡有什麼

看懂背後的決策。

01Clock reference

Use a shared clock to align all transitions.

02Reset interval

Show the reset state before normal capture begins.

03Delayed Q

Offset Q transitions from D to illustrate propagation through the flip-flop.

Use as a conceptual timing sketch; use measured delays and setup/hold windows for a sign-off analysis.

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常見問題

What does Q represent?

Q is the registered output of the D flip-flop after it captures the input at its active clock edge.

Why does Q lag D?

A physical flip-flop needs propagation time after a clock edge before its output changes.

Is this a setup-and-hold analysis?

No. It is a conceptual waveform; add explicit timing windows for a setup-and-hold review.