opamp phono preamplifier.sch
% Matlab code
close all;clear all
G=1000;
f0=1;
f1=500;
f2=50;
f3=2122;
C2=10*10^-9;
R2=1/(2*pi*f2*C2);
C3=(2*pi*f1*C2-1/R2)/(2*pi)/(f3-f1);
R3=1/(2*pi*f3*C3);
R1=(R2+R3)/G;
C1=1/(2*pi*f0*R1);
disp(['C2=' num2str(C2) ' F']);
disp(['R2=' num2str(R2) ' ohms']);
disp(['C3=' num2str(C3) ' F']);
disp(['R3=' num2str(R3) ' ohms']);
disp(['C1=' num2str(C1) ' F']);
disp(['R1=' num2str(R1) ' ohms']);
f=logspace(0,log10(30*10^3));
H=1+(R2+R3)/R1*(1+j*f/f1)./((1+j*f/f2).*(1+j*f/f3));
subplot(2,1,1);semilogx(f,20*log10(abs(H)));axis tight
xlabel('Frequency (Hz)');ylabel('dB Magnitude(H)');axis tight;grid on
subplot(2,1,2);semilogx(f,angle(H)/pi*180);axis tight
xlabel('Frequency (Hz)');ylabel('Phase(H)');grid on
% Matlab code
close all;clear all
G=1000;
f0=1;
f1=500;
f2=50;
f3=2122;
C2=10*10^-9;
R2=1/(2*pi*f2*C2);
C3=(2*pi*f1*C2-1/R2)/(2*pi)/(f3-f1);
R3=1/(2*pi*f3*C3);
R1=(R2+R3)/G;
C1=1/(2*pi*f0*R1);
disp(['C2=' num2str(C2) ' F']);
disp(['R2=' num2str(R2) ' ohms']);
disp(['C3=' num2str(C3) ' F']);
disp(['R3=' num2str(R3) ' ohms']);
disp(['C1=' num2str(C1) ' F']);
disp(['R1=' num2str(R1) ' ohms']);
f=logspace(0,log10(30*10^3));
H=1+(R2+R3)/R1*(1+j*f/f1)./((1+j*f/f2).*(1+j*f/f3));
subplot(2,1,1);semilogx(f,20*log10(abs(H)));axis tight
xlabel('Frequency (Hz)');ylabel('dB Magnitude(H)');axis tight;grid on
subplot(2,1,2);semilogx(f,angle(H)/pi*180);axis tight
xlabel('Frequency (Hz)');ylabel('Phase(H)');grid on
Opamp Notch Filter
