Automatic Gain Control (AGC)

This article is under construction!

Zenitel IP devices supports Automatic Gain Control (AGC). The purpose of the AGC feature ..............

An Automatic Gain Control (AGC) circuit is a circuit that is designed to maintain a constant output signal level after amplification, despite variations in signals at the input of the amplifier or system. This is achieved by providing more amplification to weak signals and less amplification to strong signals thus maintaining a constant signal amplitude level at the output.

Default active???

Not config in TCIV+?

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Mic Automatic Gain Control

Config Currently only for VSFT/imx28 devices. VSFF/imx6 and imx8 have "Fixed Mic Automatic Gain Control", see below:

Fixed Mic Automatic Gain Control after AEC

Not on VSFT/imx28 devices.

Fixed, not configurable block applying signal gain after AEC (compensate low mic gain before AEC), and with AGC function aiming for "nominal voice signal level".

To be used with caution and in special conditions where Near-End talker may be operating in varying distances deviating from the nominal talker distance to the station.

IC-Edge mode

Log in to the Edge Controller, and navigate to Edge Controller > System Configuration > Call and Audio, and enable/disable "AGC" per device:

Enabling AGC in an IC-Edge system

SIP and ICX-AlphaCom mode

Log in to the Zenitel IP device.

• SIP mode: Navigate to SIP Configuration > Audio Settings, and enable "Automatic Gain Control (AGC)"
• ICX-AlphaCom mode: Navigate to Advanced ICX-AlphaCom > Audio Settings, and enable "Automatic Gain Control (AGC)"

Enabling AGC on a device in SIP or ICX-AlphaCom mode (screenshot from firmware 7 and later)

Some additional settings are available in Advanced Configuration mode. Navigate to Audio Settings > Audio signal processing:

Advanced AGC settings (screenshot from firmware 7 and later)

• Enable AGC: Enable/disable the AGC component which brings the microphone signal to an appropriate range
• AGC mode: Algorithm type. Use Digital SW AGC for the majority of use cases. Analouge HW AGC is available only on Turbine devices using analogue microphone. "Analogue HW AGC" should basically be used for "Push to Talk"/"Talk back" applications and not in Open Duplex modes
  • Digital SW AGC
  • Analouge HW AGC (noisy profile)
  • Analouge HW AGC (quiet profile)
• AGC gain profile: Extent level of added gain. The target signal gain level. "Standard" shall aim to keep a "nominal voice signal level" at approx -23 dBFS. The other options will target increasingly higher signal levels. Use with caution.
  • Standard
  • Moderate
  • High
  • Very high
• AGC speed: Attack and decay rates of the algorithm.
  • Slow
  • Fast