sos2tf This function converts series second-order sections to direct H(z) = B(z)/A(z) form. [B] = sos2tf(sos) [B] = sos2tf(sos, g) [B,A] = sos2tf(...) sos: matrix of real or complex numbersSecond Order Sectional form of the system. g: real or complex value, default value is 1Gain of the system. B: Vector of numerator coefficients.Gain of the system. A: Vector of denominator coefficients.Gain of the system. This is an Octave function. This function converts series second-order sections to direct H(z) = B(z)/A(z) form. The input is the sos matrix and the second parameter is the overall gain, default value of which is 1. The output is a vector.