% BALANCED FREQUENCY DISCRIMINATOR % Vo(s)/Vi(s) = sL/(s^(2)LCR + sL + R) % [Vo(s)/Vi(s)|s^(2)=-1/L/C] = 1 R = 1; C1 = 0.0011; C2 = 0.0025; L = 0.0016; % resonance frequencies fa = 1/2/pi/sqrt(L*C1); fb = 1/2/pi/sqrt(L*C2); df = 0.05; frq = 0:df:1000; H1 = 2*pi*frq*L./ sqrt((R - (2*pi*frq).^2 * L*C1*R).^2 + (2*pi*frq).^2 * L^2); plot(frq, H1); H2 = 2*pi*frq*L./ sqrt((R - (2*pi*frq).^2 * L*C2*R).^2 + (2*pi*frq).^2 * L^2); plot(frq, H2); k = round(250/df); ka = round(85/df); kb = round(105/df); h = plot(frq(1:k+1), H1(1:k+1) - H2(1:k+1), 'k' , frq(ka+1:kb+1), H1(ka+1:kb+1) - H2(ka+1:kb+1), 'k'); set(h(1),'LineWidth',1); set(h(2),'LineWidth',2);