Question

Which of the following is the correct relation between ‘s’ and ‘z’?

(a) s=(1-z^-1)/T

(b) s=1/(1+zT)

(c) s=(1+z^-1)/T

(d) none of the mentioned

The question was posed to me during a job interview.

Question is from Backward Difference Method in chapter Digital Filters Design of Digital Signal Processing

Answer 1

Right answer is (a) s=(1-z^-1)/T

Easiest explanation: We know that z=1/(1-sT)=> s=(1-z^-1)/T.