isfir Determines whether given system function is FIR or not fir = isfir(b,a) fir = isfir(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 fir This function returns logical 1 if system is FIR (fir = 1) Otherwise it returns logical 0 (fir = 0) This function takes input a System function in terms of numerator and denumerator coefficients or in second order section (sos) matrix and checks for system having Finite Impulse Response (FIR) or not Checking given system function is FIR or not \begin{eqnarray} H(z) = 1 - z^{-1} + z^{-2} \end{eqnarray}