Low Jitter Setup - Safran WR-ZEN Series User Manual

APPENDIX
WR-ZEN TP TP-EXP
V2.2 or higher
9.8

Low Jitter Setup

Users interested in low-jitter applications of thier WR-ZEN can refer to the fol-
lowing list of recommendations to reduce jitter:
202
Device Channel
A
B
Phase noise results may be impacted by environmental factors such as tem-
perature variations, uncontrolled airflows, and mechanical vibrations.
The user must comply with the warmup time of the external reference that
is using. (For the OCXO that was used for the WR-ZEN performance data, a
24 hour warmup period was kept).
Oscillators inside WRZ LJ devices (Zen v4 and Z16 v5) need a minimum
amount of warmup time before they can reliably lock to an external ref-
erence. Typically, minimum warmup time is 10 minutes in office conditions.
This could take longer in colder environments.
Unused fiber network interfaces that have not been explicitly turned off
may add a certain amount of noise. If a user is concerned with achieving the
lowest possible phase noise, it is desirable to keep unused interfaces com-
pletely shut down (writing the command 'ifconfig wrX down' in the device
shell for each X unused interface). This can be reverted by simply writing
the command 'ifconfig wrX up'. This is not the most user-friendly approach
because it requires access to the device shell, and because this con-
figuration is lost upon reboot.
For the same reason stated right before, a user should not mix LJ and non-
LJ devices in the same setup (or, if he/she wants to do so, he/she should be
aware that the devices derived from it will have higher phase noise).
Termination at the
receiver device
1 Ohm (optimal)
50 Ohm (low volt)
1 Ohm (optimal)
50 Ohm (optimal)
High
Mode
voltage
xPPS & ~ 3.3 V
10MHz ~ 1.7 V
~ 3.3 V
xPPS & ~ 3.0 V
10MHz
WR-ZEN Series User Manual
Raise
time
1.80
ns
1.30
ns
1.80
ns
1.47
ns