1 #!/usr/bin/python

     2 

     3 from dscr import dscr

     4 import scipy as sp

     5 

     6 def myc2d(G,Ts):

     7     """ Produces numerator and denominator of discrete transfer 

     8     function in powers of z^{-1}

     9     G is continuous transfer function; time delays are not allowed

    10     Ts is the sampling time, all in consistent time units. """

    11     H = dscr(G,Ts)

    12     num1, den1 = H.num, H.den

    13     A = den1[::-1]

    14     num2 = num1[::-1]

    15     nonzero = sp.find(num1)

    16     B = num2(nonzero)

    17     k = len(den1) - len(num1)

    18     return B,A,k