Hello,

Standar peak moudule shown below is available for ADAU1446 in sigmastudio.

I would like to know about correlation among expander, compressor, knee and threshold. I need a formula correlative with those parameters to control peak via MCU not using sigmastudio. I am diffculty knowing how 34 points on the curve are made because I did not find out peak-related formula in Help.

Best Regards,

Ernest

The compressor table has 33 points, which matches the 33 points on the GUI. The calculation is actually done using 34 points stored in RAM. The first point stored in RAM represents the gain reduction value for any input below -90dB.

The exact mapping is available in this post:

http://ez.analog.com/message/5004#5004

Apparently we use some complex spline curves that are built into the Microsoft .NET Framework in order to get from the threshold/ratio values to the actual table points. However, I showed an example of how to calculate the points manually in the post above.

For a simple threshold / ratio control on a compressor, the pseudocode would be like this: