Teledyne LeCroy QPHY-DDR4 - Manual (Page 65)

QPHY-DDR4 Software Option
In the Measure section:
• tDQSH (P1) is measuring the high time of DQS. The high time is determined by measuring the time
DQS crosses Vref on a rising edge at to the time DQS crosses the next associated falling edge at
Vref. The minimum value is the measured value for tDQSH min and is reported in mtCK(avg).
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 W bursts were in the acquired waveform.
• t@tDQSHmin (P4) displays the location of where the minimum value of tDQSH occurred. This is
used to position the zoom traces at the location of the “worst case results”.
tDIPW, DQ Input Pulse Width
This test is measuring the pulse widths of the DQ signal during the W burst. Both the minimum value is
measured on both high and low pulses.
After the completion of the tDIPW test the oscilloscope is in the following configuration:
Figure 57 - Oscilloscope Configuration after the tDIPW test
Shown on this screen:
• Z3 is a zoom of F3, the acquired DQ signal after any probe deskew has been applied. The zoom is
positioned at the location of the “worst case” tDIPW measurement indicated by t@tDIPWmin. A
trace label is applied at Vref on this trace according to the signal name assigned to DQ.
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