Question

If the discrimination factor ‘d’ and the selectivity factor ‘k’ of a chebyshev I filter are 0.077 and 0.769 respectively, then what is the order of the filter?

(a) 2

(b) 5

(c) 4

(d) 3

This question was addressed to me in an internship interview.

I'd like to ask this question from Chebyshev Filters in portion Digital Filters Design of Digital Signal Processing

Answer 1

Correct choice is (b) 5

To explain: We know that the order of a chebyshev-I filter is given by the equation,

N=cosh^-1(1/d)/cosh^-1(1/k)=4.3

Rounding off to the next large integer, we get N=5.