Convert digital filter second-order section data to transfer function form
[b,a] = sos2tf(sos)
[b,a] = sos2tf(sos,g)
sos2tf converts a second-order section representation of a given digital filter to an equivalent transfer function representation.
[b,a] = sos2tf(sos) returns the numerator coefficients b and denominator coefficients a of the transfer function that describes a discrete-time system given by sos in second-order section form. The second-order section format of H(z) is given by
sos is an L-by-6 matrix that contains the coefficients of each second-order section stored in its rows.
Row vectors b and a contain the numerator and denominator coefficients of H(z) stored in descending powers of z.
Compute the transfer function representation of a simple second-order section system.
sos = [1 1 1 1 0 -1; -2 3 1 1 10 1]; [b,a] = sos2tf(sos)
b = -2 1 2 4 1 a = 1 10 0 -10 -1