function plot_g1(R1,R2,C1,C2,fmin,fmax)

for f=fmin:fmax;
g(f) =(20*log(abs((1/(R1*R2*C1*C2))/(((j*2*pi*f)^2)+(j*2*pi*f)*((1./(R1*C1))+(1/(R2*C1))+(1/(R2*C2)))+(1/(R1*R2*C1*C2))))));
end

semilogx(g)

end