When Dtft and Zt Are Equal?

When do DTFT and ZT are equal? When r=1, z = e^jω and hence DTFT and ZT are equal.

Under what condition z-transform is same as discrete Fourier transform?

In other words, if you restrict the z-transoform to the unit circle in the complex plane, then you get the Fourier transform (DTFT). 2. One can also obtain the Z-Transform from the DTFT. So the z-transform is like a DTFT after multiplying the signal by the signal $ y[n]=r^{-n} $.

What is the merit of z-transform over DTFT?

A significant advantage of the z-transform over the discrete-time Fourier transform is that the z-transform exists for many signals that do not have a discrete-time Fourier transform. Thus, it is a more general analysis tool.