Increase Gain Value in sigma studio

Hello ushak,

This has to do with the number format and the number of available bits. A unity gain signal is a 1.23 signal where the "1" is a 1 and the rest all zeros will give us a gain factor of 1.

Internally the DSP is 28 bits and the 24 bits of the serial inputs and the ADC inputs are mapped to be the 1.23 signal. The sign is extended to end up with a 5.23 number as the 28 bits. When you do not count the sign bit this is only four bits to represent a number above a "1". with ~6dB per bit the four bits means you can only boost another 24dB. You simply run out of numbers. A 15.9999 is the largest positive number you can represent and that as a gain factor is ~+24dB.

This is super easy to solve. We do it all the time. You simply cascade two gain cells in a row. However, be careful. You can easily clip a signal.

Here is an example where I demonstrate around 30dB of gain.

Dave T