isstable Checks stability of given Discrete time system function flag = ismaxphase(b,a) flag = ismaxphase(sos) b Coefficients of numerator polynomial of system function a Coefficients of denumerator polynomial of system function sos Second order section matrix of order Kx6 flag This function returns logical 1 if system is Stable (flag = 1) Otherwise it returns logical 0 (flag = 0) This function determines whether the given system function is Stable system function or not. Stable system means all poles of transfer function will be inside the unit circle in z-plane \begin{eqnarray} H(z) = \frac{1 +2z^{-1} } {1 -0.7z^{-1} + 0.1 z^{-2} } \end{eqnarray} \begin{eqnarray} H(z) = \frac{1 +2z^{-1} } {1 +5z^{-1} + 6z^{-2} } \end{eqnarray}