Transition Networks Contra Converter Quick Setup Guide
provide a true representation of the network and do not generate the specific packet profile
required by Mode 2. Users of simulator and simulation packages should be aware that
Clock Mode 2 may not be suitable.
• It is recommended that the Frames per Packet value on each Logical Link be set to a
value of less than 40 when using mode 2 to ensure optimum clock recovery performance.
Mode 3: Known as Adaptive Frequency. It is suited to low quality networks, and networks
where changes to the clock recovery offset have a greater impact on the system devices.
The DCO value is changed very infrequently. Please consult the below table for information
on how long PacketBand takes to go into each clock recovery state using the different modes
available.
Recovery
Time to go to
Acquiring state (s)
Time to go to
Acquired state (s)
All times shown are approximate, and can be affected by the Clock Recovery Filter, Jitter
Buffer, Frames per Packet and Network conditions on a system.
Clock Recovery Filter
Clock Recovery filter (1 or 2). The Clock Recovery Filter is used to set the size of the window
which PacketBand uses to look for clocking information received from the master
PacketBand. Using Filter 2 narrows the search window, so that clocking information can be
found more quickly and the unit will enter the Acquired state faster. The downside to using
Filter 2 is that an increase in jitter or network latency will have a greater effect on PacketBand.
It is recommended that Filter 2 is only used on high quality IP networks with very low Jitter
and a latency of 10ms or less.
UDP Base Port No.
Base Port Number for the UDP. The first logical link uses this port number. The second
logical link uses this port number plus one, the third uses this port number plus two, etc.
For logical links that are not idle, changes take effect the next time the link is restarted.
PPM Tolerance
Clock recovery tolerance in parts per million. The PPM tolerance option can be used to offset
the frequency of PacketBand's on-board oscillator. This can be used for fine tuning
clock recovery within a system. This is an advanced feature, and should not be adjusted
without a full understanding of the consequences. Please contact Transition Networks if fine
clocking adjustments are required.
Underrun Type
Underrun type (Fixed Byte or Last Byte). Specifies what value to use for a TDM timeslot
when an underrun occurs. Fixed Byte uses a specified value, Last Byte uses the last known
value. For logical links that are not idle, changes take effect the next time the link is restarted.
Underrun Byte Value
Underrun Byte Value if Fixed Byte selected. When the underrun type is Fixed Byte, this is the
value that will be used for a TDM timeslot when an underrun occurs. For logical links that are
not idle, changes take effect the next time the link is restarted.
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