%
%  freq1.
%
R1 = 98.8; % kOhm
R2 = 978; % kOhm
R3 = 100.6 % kOhm
C1 = 10.4*1e-6; % mFarad

f = 10:1e4; 
H = (1+R3/R2)./(1+(2*pi*i*f)*R1*C1);
G = 20*log10(abs(H));
semilogx(f,G,'k','linewidth',1.5)
xlabel('\omega   (Hz)','fontsize',14)
ylabel('Gain   (dB)','fontsize',14)
grid