The function "ztrans" returns the Z-transform of a symbolic expression/symbolic function with respect to the transformation index at a specified point. For example, the line of code
ztrans(f,trans_index,eval_point)
computes the Z-transform of f with respect to trans_index at point eval_point. For a given difference equation, say, y(n)=0.8y(n-1)+0.4u(n), the Z-transform can be computed as follows:
syms y(n) z;
eq=y(n)-0.8*y(n-1)-0.4*heaviside(n);
Zeq=ztrans(eq,n,z)
The output of the above is as follows:
Zeq =
ztrans(y(n), n, z) - 2/(5*(z - 1)) - (4*ztrans(y(n), n, z))/(5*z) - (4*y(-1))/5 - 1/5
In this case, the Z-transform of y(n-1) is correctly replaced by (1/z)*ztrans(y(n)).
Refer to the following link for more information about the computation of Z-Transforms using MATLAB:
