How to adapt 4th order IIR filter coefficients from matlab to cmsis dsp biquad struct
% design the filter as poles, zeroes and gain
[z,p,k] = butter(2,[445 561]*2/48000);
% turn into biquads
sos = zp2sos(z,p,k);
% eliminate a0
coeffs = sos(:,[1 2 3 5 6]);
% make a linear array
coeffs = [coeffs(1,:) coeffs(2,:)];