gPTP / STBM Time Synchronization Visualizer

gPTP timestamping & correction — HW timestamps shown on the node that captures them

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Domain Master

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0 ms

Grandmaster

Master HW timestamps

t₁preciseOriginTimestamp — Sync egress

t₂Pdelay_Req ingress

t₃Pdelay_Resp egress

ccorrectionField — residence time

IEEE 802.1AS gPTP · two-step — t₁…t₄ shown at the arrow endpoint that captures them

Sync Follow_Up Pdelay_Req Pdelay_Resp Pdelay_Resp_Follow_Up

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Slave UNSYNCHRONIZED

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0 ms

STBM sync time—

HW RX timestamp—

Poll notify delay—

timeLeap status—

Slave HW timestamps

t₁Pdelay_Req egress

t₂Sync ingress — MAC HW ts

t₄Pdelay_Resp ingress

Δppoll notify delay — RX poll + bus load

Configuration

Master clock Clock frequency (kHz) 0 ppm Sync / Follow_Up interval (ms) Commanded time shift (ms, vs master)

Slave internal clock Clock frequency (kHz) 0 ppm Oscillator stability (%, ≤ 0.1) Correction mode Cycle time (ms) Freeze slave clock (stop oscillator) Sync-loss timeout (ms → revert to UNSYNC) STBM time-leap threshold (ms, |correction| ≥ → timeLeap) Accept all syncs (disable 6.25% reject)

gPTP link Target accuracy (µs) Pdelay interval (ms) Static path delay (µs, Pdelay off) Residual link noise (µs, ±) Sync arrival jitter (ms, ±) Frame animation speed 0.40×

Slave Eth RX (polling) Ethernet HW timestamping RX polling period (ms) Bus traffic load (%) 40% Max contention delay (ms)

Timestamp values — master & slave timers counting up

Time view: 4.0 s

master timer slave timer received master ts (Sync/Follow_Up) sync applied sync rejected

Event log

Slave calculation

① Peer path delay (slave-computed)

δ meanPathDelay = ((t₄ − t₁) − (t₃ − t₂)) / 2

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② Offset from master

offsetFromMaster = t₂ − t₁ − δ − c − Δp

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Deviation (slave − master) 0.000 ms

gPTP accuracy (±500 µs) — within target

Plausibility window (6.25%) — since last sync

Cycle-to-cycle jitter 0.000 ms limit < 1 ms

rateRatio (master / slave) — frequency servo

Sim time 0 ms 0 syncs

Clock deviation over time

slave − master ±500 µs accuracy 6.25% plausibility envelope sync applied sync rejected

Timer counts (oscillator ticks) — slope = clock frequency

master timer count slave timer count same frequency → same slope

gPTP / STBM Time Synchronization