Teledyne LeCroy QPHY-SAS3 - Manual (Page 23)

QPHY-SAS3 Software Option
Tx Group 3 (Link Stability, Common Mode, … WDP)
There are 7 tests run in this group. The tests that are run are:
1. Tx 5.3.1 Phy Link rate Stability (HFTP)
2. Tx 5.3.2 Common Mode RMS Voltage (CJTPAT)
3. Tx 5.3.4 and 5.3.5 Vpp, VMA, EQ (D30.3)
4. Tx 5.3.6 Rise and Fall Times (HFTP)
5. Tx 5.3.7 RJ, (MFTP, MFTP-SSC-DOWN, MFTP-SSC-CENTER)
6. Tx 5.3.8 TJ, (MFTP, MFTP-SSC-DOWN, MFTP-SSC-CENTER)
7. Tx 5.3.9 Waveform Distortion Penalty
Each of these tests are described in detail below.
Tx 5.3.1 Phy Link Rate Stability (HFTP)
The purpose of this test is to characterize the quality and consistency of the transmitter’s reference clock
by measuring the physical link rate long term stability. After the completion of the Phy Link Rate Stability
test the oscilloscope is in the following configuration:
Figure 13 - Oscilloscope Configuration after Phy Link Rate Stability Test
Shown on this screen:
• 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.
922545 Rev A 23