Minimum Delay For Adaptive Jitter Buffer - Siemens HG 3500 V4 Service Manual

gateways_02_terms.fm
Terms
Jitter Buffer
20
Key: Maximum delay (configurable)
Average delay (configurable)
Measured average delay
Del
ay
Measured time
Figure 9 Clock drift in static jitter buffer [transmission slower than receipt]
If, for example, the average delay has been set to 40 ms, this means that the
measured overall delay is reduced at intervals from the start value by 40 ms. The
length of the interval depends on the clock pulse difference of the clock pulse
generators in the central system (for all HG 3500 systems) or on the HG 3575
boards as well as on the configuration data (difference between the maximum
and the average values). In the sample configuration (40 ms delay hub) the
interval is between approximately 30 and 120 minutes long.
The variation in the overall delay caused by clock drift can be completely avoided
by synchronizing the components involved with a common clock pulse.

2.5.5 Minimum Delay for Adaptive Jitter Buffer

In adaptive working mode, the jitter buffer tries to keep the average delay as low
as possible. In a situation where no jitter effect occurs, the average delay drops
to a minimum. This minimum can be configured in the HG board. The average
delay, which is continuously adapted based on the current delay measured,
ranges between two values: the configurable minimum delay and the
configurable maximum delay. The following diagram illustrates this:
HiPath 4000 V5, IP Solutions - HG 3500 & HG 3575, Service Documentation
A31003-H3150-S104-2-7620, 03/2009