Question

Given a m-derived low pass filter has cut-off frequency 1 kHz, design impedance of 400Ω and the resonant frequency of 1100 Hz. Find the value of m.

(a) 0.216

(b) 0.316

(c) 0.416

(d) 0.516

The question was posed to me in an international level competition.

Origin of the question is m-Derived T-Section topic in section Filters and Attenuators of Network Theory

Answer 1

Right answer is (c) 0.416

To explain: m=√(1-(fc/fr)^2) fc = 1000, fr = 1100. On substituting m=√(1-(1000/1100)^2)=0.416.