Teledyne LeCroy QPHY-DDR4 - Manual (Page 38)

Eye Diagram Tests (CKdiff-DQSdiff-DQse)
There are 5 tests run in this group. The tests that are run are:
Eye Diagrams on W bursts
1. Write Bursts (Inputs) - DQ and DQS Eyes
2. DQ Input Compliance Mask
3. VIHL_AC, DQ AC Input Swing Pk-Pk
Eye Diagrams on R bursts
4. Read Bursts (Outputs) - DQ and DQS Eyes
5. VOHL_AC, DQ AC Output Swing Pk-Pk
Each of these tests is described in detail below.
Write Bursts (Inputs) - DQ and DQS Eyes
This is an informational only test that creates an eye diagram for DQ and DQS of all of the W bursts
detected in the acquisition. DQS is the timing reference for both eye diagrams and the reference point is
shown on the center screen.
After the completion of the Write Bursts (Inputs) - DQ and DQS Eyes the oscilloscope is in the following
configuration:
Figure 22 - Oscilloscope Configuration after Write Bursts (Inputs) – DQ and DQS Eyes
Shown on this screen:
• F6 is the DQS eye diagram of the W bursts from the acquired signal. DQS is used as the timing
reference for this test which causes the eye to come to a “pin point” on the center grid. This math
function is assigned an alias based on the assigned DQS signal name. The number of bits
38 924291 Rev A