Media5 Mediatrix 4104, Справочное руководство

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Echo Cancellation Reference Manual (SIP Version)
Mediatrix 4104 243
The following settings are available:
See “Enabling Individual Codecs” on page 231 for more details.
Echo Cancellation
Echo cancellation eliminates the echo effect caused by signal reflections. An echo is a signal that has been
reflected or otherwise returned with enough magnitude and delay to be perceived. The echo cancellation is
usually an active process in which echo signals are measured and cancelled or eliminated by combining an
inverted signal with the echo signal.
You can disable the echo cancellation feature of the Mediatrix 4104, which may be useful to ensure the
success of some modem transmissions.

To enable or disable echo cancellation:
1. In the voiceIfMIB , set the voiceIfEchoCancellationEnable variable to the proper value.
Signal Limiter
If you are experiencing echo issues, you may use the Signal Limiter. When enabled, the Signal Limiter
attenuates or removes peaks in the voice signal.

To use the Signal Limiter:
1. In the voiceIfMIB , set the voiceIfSignalLimiterLevel variable to the proper value.
Table 157: G.729 VAD Settings
Setting Description
disable G.729 uses annex A only. The Mediatrix 4104 does not send G.729 Annex B
comfort noise frames.
enable G.729 annex A is used with annex B. The Mediatrix 4104 sends G.729 Annex
B comfort noise frames during silence periods.
Table 158: Echo Cancellation Parameters
Parameter Description
disable The DSP does not use echo cancellation on the related port.
enable The DSP proceeds to cancel signals that are recognized as echo when
appropriate. This is the default value.
Caution:
This may reduce the presence of echo but may impair DTMF detection because of the signal
distorsion.
Table 159: Signal Limiter Parameters
Parameter Description
0 Disable signal limiter
1 Most aggressive
...
5 Least aggressive