Create pure continuous-time delays
d = exp(tau,s)
d = exp(tau,s) creates pure continuous-time delays. The transfer function of a pure delay tau is:
d(s) = exp(-tau*s)
You can specify this transfer function using exp.
s = zpk('s') d = exp(-tau*s)
More generally, given a 2D array M,
s = zpk('s') D = exp(-M*s)
creates an array D of pure delays where
D(i,j) = exp(–M(i,j)s).
All entries of M should be non negative for causality.