FAQ
Q: What are the typical figures for ADEV and Jitter that I may expect with a WR Switch with the low jitter board?
Modified ADEV at 1s < 5E-13 (typical 4E-13)
Modified ADEV at 10s < 5E-14
Jitter (10 Hz to 100 kHz) < 2 ps RMS (typical 1.5 ps
RMS)
Q: In a system with a standard WR Switch in Grandmaster mode, will another WRS with low jitter board further down in the network benefit improve jitter?
A: No, because the noise of the standard Grandmaster is very high it will not help to have lower down in the network better switches. You will see more improvements if you make use as Grandmaster a WR Switch that has the low jitter daughterboard in it.
Q: Can I benefit of the performance of WRS Low jiiter board if the GM is using it but the boundary switch is a standard one?
A: Yes, you will experience a 10 dB reduction of noise.
Better improvements can be achieved if
-
you cover the boundary VCTCXO (VM53S3) of RTV3140 silicone resin (hardware modification) OR
-
you increase the bandwidth of the boundary VM53S3 (software modification) with Kp=10000 and Ki=300
Q: What to do if I want to have the very best jitter performance?
A: Switch off the Ethernet management interface. The jitter will be
slightly improved by 10 to 20%. The stability will not change.
See the measurement
results.
Likely the small improvement you may get will not be worth it as you
will not be able to manage your switch remotely over Ethernet anymore.
24 March 2017