Teledyne LeCroy QPHY-SAS2 - Manual (Page 31)

QPHY-SAS2 Software Option
917718 Rev A
31

F2 is the SSCTrack of the input. This signal is filtered by a 1
st
order Butterworth filter with a 3.7 MHz cutoff
as described by the specification. The first division of the result is discarded to allow for clock recovery
“capture” as well as settling of the startup effect of the filter. This is the same as creating the SSCTrack,
however, when SSC is not enabled on the device, we can use this to calculate the long term stability.
Figure 22 - Phy Link Rate Stability Test Results
In the Measure section:

P1 and P2 are used to calculate the min and the max of F2. These are the measured values for Tx – Min
Phy Link Rate Stability (5.3.1) and Tx – Max Phy Link Rate Stability (5.3.1). These values must be
between +/- 100ppm in order to pass this test.
Tx 5.3.2 Common Mode RMS Voltage (CJTPAT)
The purpose of this test is to verify that the common-mode RMS voltage is within the specification limits. After the
completion of the Common Mode RMS Voltage test the oscilloscope is in the following configuration:
Figure 23 - Oscilloscope Configuration after the Common Mode RMS Voltage Test
Shown on this screen

F2 is the Common Mode Trace. This is calculated by summing the 2 inputs and dividing by 2.
Figure 24 - Common Mode RMS Voltage Results