Question

A system has fourteen poles and two zeros. Its high frequency asymptote in its magnitude plot having a slope of 
1. -40 dB/ decade
2. -240 dB/ decade
3. –280 dB/decade
4. –320 dB/ decade

Answer 1

Correct Answer - Option 2 : -240 dB/ decade

Concept:

A pole decreases the slope by 20 dB while a zero increases the slope by 20 dB.

With 'p' poles and 'z' zeroes only, the system will have have a maximum slope of:

(z - p) × 20 dB/decade

Calculation:

Given n = 14 and z = 2

Maximum slope will be:

(z - p) × 20 dB/decade

= 20 (2 - 14) dB/decade

= -240 dB/decade