Teledyne LeCroy QPHY-DDR4 - Manual (Page 58)

t@tDQSCKmax. A trace label is applied at Vref on this trace according to the signal name
assigned to DQS.
Figure 48 – tDQSCK Results
In the Measure section:
• tDQSCK (P1) is measuring the skew between CK and DQS. The skew is measured between
CK
rising at Vref to the nearest DQS rising at Vref . Essentially the time between the two trace labels is
measured. The maximum value is the measured value for tDQSCK max. This test is considered
informational only since the limit is undefined.
• tDQDQS (P2) is measuring the skew between DQ and DQS. Since this measurement is performed
once per burst, this shows how many R bursts were in the acquired waveform.
• t@tDQSCKmax (P4) displays the location of where the minimum value of tDQSCK occurred. This is
used to position the zoom traces at the location of the “worst case results”.
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