and this MATLAB script:
% Bode.m - plot the Bode plot of a network function
%---------------------------------------------------------------
% Create a list of logarithmically spaced frequencies.
%---------------------------------------------------------------
wmin=1; % starting frequency, rad/s
wmax=10000; % ending frequency, rad/s
w = logspace(log10(wmin),log10(wmax));
%---------------------------------------------------------------
% Enter values of the parameters that describe the
% network function.
%---------------------------------------------------------------
K= 10; % constant
z= 100; % zero
p1=10; p2=1000; % poles
%---------------------------------------------------------------
% Calculate the value of the network function at each frequency.
% Calculate the magnitude and angle of the network function.
%---------------------------------------------------------------
for k=1:length(w)
H(k) = K*(1+j*w(k)/z) / ( (1+j*w(k)/p1) * (1+j*w(k)/p2) );
mag(k) = abs(H(k));
phase(k) = angle(H(k));
end
%---------------------------------------------------------------
% Plot the Bode plot.
%---------------------------------------------------------------
subplot(2,1,1), semilogx(w/(2*pi), 20*log10(mag))
xlabel('Frequency, Hz'), ylabel('Gain, dB')
title('Bode plot')
subplot(2,1,2), semilogx(w/(2*pi), phase)
xlabel('Frequency, Hz'), ylabel('Phase, deg')
Here’s the Bode plot produced by running the MATLAB script:
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