Teledyne LeCroy QPHY-DDR2 - Manual (Page 35)

QPHY-DDR2 Software Option
QPHY-DDR2-OM-E Rev A
35
tCH(avg), Average High Pulse Width
tCH(avg) is defined as the average high pulse width, as calculated across any consecutive 200 high pulses.
tCH(avg) = SUM(tCHi) / (200 x tCK(avg)) where I = 1 to 200
See Figure 20 as follows.
tCL(avg), Average Low Pulse Width
tCL(avg) is defined as the average low pulse width, as calculated across any consecutive 200 low pulses.
tCL(avg) = SUM(tCLi) / (200 x tCK(avg)) where i=1 to 200
See Figure 20 as follows.
Figure 20. Data output (read) timing [JESD79-2E figure 32]
tCH(abs), Absolute High Pulse Width
tCH(abs) is defined as the absolute high pulse width, of each of 200 consecutive high pulses.
tCL(abs), Absolute Low Pulse Width
tCL(abs) is defined as the absolute low pulse width of each of 200 consecutive low pulses.
tJIT(duty), Half Period Jitter
Applicable only to 667 and 800 MHz device only.
tJIT(duty) is defined as the cumulative set of tCH jitter and tCL jitter over 200 consecutive cycles.
tCH jitter is the largest deviation of any single tCH from tCH(avg).
tCL jitter is the largest deviation of any single tCL from tCL(avg).
tJIT(duty) = Min/max of {tJIT(CH), tJIT(CL)}
where,
tJIT(CH) = {tCHi - tCH(avg) where i=1 to 200}
tJIT(CL) = {tCLi - tCL(avg) where i=1 to 200}