Teledyne LeCroy QPHY-SAS2 - Manual (Page 33)

QPHY-SAS2 Software Option
917718 Rev A
33
Figure 26 - Vpp, VMA and EQ Results
In the Measure section:

Vpp (P1) is measuring the full range of the F4 histogram. This is the measured result for Tx - Vpp (5.3.4).
This value must be between 850mV and 1.2V in order to pass this test.

LowMode (P4) is the maximum peak from the left side of the F5 waveform. This represents the de-
emphasized low voltage level of the signal.

HighMode (P5) is the maximum peak from the right side of the F5. This represents the de-emphasized high
voltage level of the signal. These are used to calculate the VMA.

VMA (P6) is the difference between the 2 modes of the histogram. This is the measured value of Tx - VMA
(5.3.5). This value must be less than 600mV in order to pass this test.

EQ (P8) is calculated as 20*log
10
(V
p-p
/VMA). This is the measured value of Tx - EQ (5.3.5). This value must
be between 2 and 4 dB in order to pass this test.
Tx 5.3.6 Rise and Fall Times (HFTP)
The purpose of this test if to verify that the rise and fall times are within the specification limits. After the
completion of this test the oscilloscope is in the following configuration:
Figure 27 - Oscilloscope Configuration after the Rise and Fall Times Test
Shown on this screen:

F1 is the differential input waveform.