bode.m

w = logspace(-1,5,50); 

for i = 1:length(w) 
    if (w(i) <= 36) 
        magn(i) = 20*log10(w(i)) + 20*log10(92)
    elseif (w(i) <= 1800) 
        magn(i) = 20*log10(w(i)) + 20*log10(92) -20*log10(w(i)/36)
    elseif (w(i) <=100000)
        magn(i) = 20*log10(w(i)) + 20*log10(92) -20*log10(w(i)/36) -20*log10(w(i)/1800)
    else
        magn(i)=0
    end 
end 

subplot(2,2,1);
semilogx(w,magn); grid; hold on; 

tf1 = tf(1,[1 36]); [mag1,phase1] = bode(tf1,w); % compute the phase of the 1st term 
tf2 = tf(1,[1 1800]); [mag2,phase2] = bode(tf2,w); % compute the phase of the 2nd term 
totalph = phase1 + phase2; % add these up to get the total phase 
subplot(2,2,2);
semilogx(w, totalph(1,:)); grid; hold on


H=tf([92 0],[1/64800 17/600 1])
subplot(2,2,3); 
bodemag(H)


subplot(2,2,4);
h=bodeplot(H)
setoptions(h,'MagVisible','off');