Auto Gain Control | Virtual View - AVX Architect
This video covers the Auto Gain Control (AGC) object in the Virtual View of AVX Architect, part of a series on audio processing objects. The AGC object is used to keep the average level of a signal at a constant level by adding or removing gain. You’ll learn AGC-specific terminology, explore its factory panel, see where to find it in the Virtual Library, and learn how to add it to your workspace for system design.
Transcript
. In this video, we’ll continue to explore the Virtual View of AVX Architect and look at the Automatic Gain Control object, or AGC. The AGC object is found in the virtual view, under the “Dynamics” section of the audio processing objects. The AGC object is used to keep the average level of a signal at a constant level by adding and removing gain from a signal to reach the desired level. High level signals are reduced by a fast limiter to prevent distortion by clipping.
Let’s look at some of the parameters in the AGC factory panel. Threshold is the level at which the AGC will recognize a signal as a legitimate level to be increased to the AGC target level. This lower limit will prevent the AGC from adding gain to low level signals or noise. Gain is the maximum amount of gain that can be applied to reach the target level. The Target, is the user defined optimum signal level to be achieved and maintained. Window is the size of the window or range around the target. Decreasing the size of the window will result in tighter control of the signal. Attack is the amount of time it takes for gain or reduction to be applied after a signal crosses the threshold. Release is the rate of change that takes place after the signal has fallen below the threshold. This gain reduction meter will show gain increase or reduction being applied to the signal.
On the right, we can see the final stage limiter adding extra protection. When the signal level reaches the limit threshold, gain will be reduced with an 8:1 ratio. This limiter also has a user-defined threshold that can be changed with the threshold control. By default, Auto is enabled, which will dynamically set the limiter’s attack and released parameters based on the input signal. Turning it off, we can set these values manually. This is the on/off switch for the AGC processing. When off, the processing will not occur, acting as a bypass. Finally, the Revert button will return all parameters to the values when the panel was last opened.
At the top of the factory panel, we have our usual object name, lock button, and selection mode switch. On the right, the “Properties” window has the usual naming, workspace location, and DSP allocation options. The “Options” section contains the usual channel count of the object block. Like our other dynamics processing objects, channel count is limited to 128 channels.