Teledyne LeCroy QPHY-DDR4 - Manual (Page 42)

In the Measure section:
• tBurst R (P2) displays the number of R bursts detected in the acquisition.
• ClockFreq (P8) is the measured clock frequency from the acquired waveform.
VOHL_AC, DQ AC Output Swing Pk-Pk
This is an informational only test that creates an eye diagram for DQ in all of the R bursts detected in the
acquisition. DQS is the timing reference for this eye. Additionally, VOHL_AC will test the peak to peak
amplitude of the DQ signal for each UI. It is measured as a peak to peak voltage centered at Vref.
After the completion of the DQ Read Eye the oscilloscope is in the following configuration:
Figure 28 - Oscilloscope Configuration after DQ Read Eye Test
Shown on this screen:
• F7 is the DQ eye diagram of the write bursts from the acquired signal. The DQS signal is the timing
reference for this eye diagram. This math function is assigned an alias based on the assigned DQ
signal name. The number of bits contained in the eye diagram is displayed in the bottom row of
the F7 descriptor box. In this case there are 7,000 DQ bits in the eye.
In the Measure section:
• tBurst R (P2) displays the number of R bursts detected in the acquisition.
• ClockFreq (P8) is the measured clock frequency from the acquired waveform.
• VOHL_AC (P11) calculates the minimum eye opening for each UI. This value is provided as
informational only and is analogous to the VIHL_AC measurement on the W bursts.
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