ActiveFilter1.m

param1 = 0.5; % knob 0 to 1
Fs = 44100.0;

R1 = 330e3;
C1 = 220e-12;
R2 = 3.3e3;
C2 = 10e-9;
Rp = 100e3 * param1;

Num = [(R1*C1*(Rp+R2)*C2) (C2*(Rp+R2)+R1*C1+R1*C2) 1.0];
Den = [(R1*C1*(Rp+R2)*C2) (C2*(Rp+R2)+R1*C1) 1.0];

[H,W] = freqs(Num, Den);
Freq = W/(2*pi);
Mag = 20*log10(abs(H));
semilogx(Freq, Mag);
grid on;
grid minor;

%[z,p,k] = tf2zp(Num, Den);