Teledyne LeCroy QPHY-DDR4 - Manual (Page 64)

tDQSH/tDQSL, DQS Input High/Low Pulse Width
These tests measure the high (tDQSH) and low (tDQSL) pulse widths of each DQS signal during a W
burst. Both the maximum and minimum tDQSH/tDQSL values are measured.
This tests are very similar to
tQSH and tQSL, which are measured on R bursts.
Note: Only tDQSH will be discussed below. The measurement methodology is the same for the
tDQSL expect the measurement is made on DQS from falling edge to a rising edge instead of a rising
edge to a falling edge.
After the completion of the tDQSH test the oscilloscope is in the following configuration:
Figure 55 - Oscilloscope Configuration after the tDQSH test
Shown on this screen:
• Z2 is a zoom of F2, the acquired DQS signal after any probe deskew has been applied. The zoom is
positioned at the location of the “worst case” tDQSH measurement indicated by t@tDQSHmin. A
trace label is applied at Vref on this trace according to the signal name assigned to DQS.
Figure 56 – tDQSH/tDQSL Results
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