Automatic Gain Control
Hi i'm new to the world of DSP and i'm using the ADAU1701 is it possible to create a automatic gain control.
if so how do i start?
Audio Signal Processors
SigmaDSP Audio Processors
adau1701
Hi Steve,
The simplest implementation of an ALC is using a dynamics processor to emphasize the signal range of interest. It can vary a lot based on the application, but here are some rules of thumb and a few tips.
Route the input signal to a dynamics processor, preferably through a crossover network. This way you can have separate detection and processing for multiple bands, which should improve the overall quality of the ALC.
Here's an example of a mono, dual-band ALC.
The crossover in my example is configured with a crossover point of 300 Hz.
Set up an ALC curve to emphasize the gain region of interest.
These are very broad suggestions. The actual implementation and tuning of the dynamics processors depends highly on different system factors.
Note that our ADAU1761 has a built-in hardware ALC, which would be a simpler solution and doesn't require DSP. Refer to its datasheet for more info.
is there away to maintain a constant level even if the original input signal was very low in one case and loud in another?
If you use the dynamics processor to boost the level of quiet signals and reduce the level of loud signals, a more constant level will be output. This is just applying compression on both the high-level and low-level signals to compress the dynamic range of the signal.
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Thank you,
EZ Admin
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