The single precision filter has a ploblem.
Examples are as follows. Here, f = 30Hz, Q = 1.41, Boost = 1dB
1. The level12 readback data is -48dB.
I add a DC filter(DCB2), and the level3 read back is -65dB smaller than before. But the problem is still very serious.
2. Problems have improved use the double precision filter. But there is still no complete solution.
So, I don't dare to use the single precision filter now.