Module ztransform 

Z-transform X(z) = Σ_{n≥0} x[n] z^{−n} of a finite causal sequence, evaluated at a complex z, plus the standard closed forms for the unit step and the geometric sequence.

Functions

geometric_z

Closed form for a^n u[n]: X(z) = 1/(1 − a·z^{−1}), valid for |z| > |a|.

unit_step_z

Closed form for the unit step u[n]: X(z) = 1/(1 − z^{−1}) = z/(z−1), valid for |z| > 1. None at z = 0 or z = 1.

z_transform_finite

X(z) = Σ_{n=0}^{N−1} x[n] z^{−n} for a finite real sequence. None at z = 0.