Comrex Access NX, Руководство по эксплуатации продукта

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Decoder Downmix - This allows the decoded “stereo” (two-channel) audio that arrives at the receive end to be
downmixed to a mono signal. The choices are None , Mono Left Only , Mono Right Only , and Mono Full . Except
for None , these are mainly used for sending two different mono streams to two different destinations at the
same time. For more information on these choices, see “APPENDIX D - USING THE COMREX ACCESS DECODER
DOWNMIX FUNCTION” on page 121 .
Loss Cushion - This choice instructs the buffer manager to ignore a certain percentage of late packets in its
calculation. The default value is 5%. Applications that are not at all delay sensitive may wish to reduce this value to
zero, while extremely delay sensitive applications may prefer to have this closer to 25%. By eliminating packets that
arrive extremely late, delays can be reduced greatly. The decoder error concealment does a very good job of hiding
any losses that may result.
Loss Cushion Mode – This mode ensures that the unit will show losses in terms of percentile of packets lost.
Retransmit Squelch Trigger and Retransmit Squelch Max - These options are used to determine how the buffer
manager reacts to typical data dropouts, like those seen on some wireless networks. If the data protection causes
retransmission of data packets during a signal fade, this can cause the network protection layer to “fight” the buffer
manager, expanding the buffer and increasing the delay, with no real benefit.
The Retransmit Squelch capability allows the decoder to detect these events and avoid having the buffer manager
react. These should normally be left where they are, but may be changed if dropouts are a problem.
The Retransmit Trigger function determines the amount of time the decoder must experience 100% packet loss
before the Retransmit Squelch function is triggered. Default is one second.
The Retransmit Squelch Max function determines the longest period of data loss during which the squelch function
is active. The default is two seconds. During the squelch period, the buffer manager will ignore the relative jitter
experienced and will not adjust buffer size to compensate.
Fixed Delay - This option simply sets the Delay Cushion and Delay Limit at a similar value, so that the delay buffer is
defined to the chosen value and will not increase or decrease significantly.
Delay Cushion - The Delay Cushion setting instructs the jitter buffer manager to not attempt to drive the delay
below a certain value. For example, if the delay cushion is set to 500mS, that amount of fixed delay will be added to
the buffer. If the jitter manager needs to increase the buffer it will do so, but will not fall below the ½ second level.