Clock Edge Time Three-Row Scan - Electronic Circuits IV & XII: Digital Logic and Timing Closure Step by Step

A clock edge time is the selected edge index multiplied by the period, so the scan varies index and period together to show where each edge lands. The rows 1 times 2 s equals 2 s, 4 times 2 s equals 8 s, and 5 times 3 s equals 15 s are exact for the ideal uniform-clock model; real clocks add jitter, skew, duty-cycle distortion, PVT variation, aperture uncertainty, routing delay, and timing measurement uncertainty.

Edge time is the selected index multiplied by the clock period. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Edge one at two-second period lands at two seconds

With period 2 seconds, selected edge 1 occurs at 2 seconds.

1\cdot2\ \text{s}=2\ \text{s}

Edge four at the same period lands at eight seconds

With period 2 seconds, selected edge 4 occurs at 8 seconds.

4\cdot2\ \text{s}=8\ \text{s}

A larger period and later edge land at fifteen seconds

With period 3 seconds, selected edge 5 occurs at 15 seconds.

5\cdot3\ \text{s}=15\ \text{s}