control system bode plot

how to plot this two equatio and the resutant output is shown in the figure

the alpha value should be any fractional value(eg-alpha=0.01 to 0.09).

one of the matlab community person helped me but his alpha value is 1 not fractional the code is given below

(hold off;

alpha=1;Wcr=10;

w1=logspace(-1,log10(Wcr),1000);w2=logspace(log10(Wcr),3,1000);

Mag1=20*ones(1,numel(w1));Mag2=@(w2) 20*alpha*log10(w2);

semilogx(w1,Mag1);hold on;semilogx(w2,Mag2(w2));grid on;xlabel('Frequency');ylabel('dB'))

[Irshad Baruah]

thanx ammer

[Walter Roberson]

Irshad Baruah:

If you believe that your question is unclear, then since you are the person who posted the question, you have the responsibility to clarify it.

Answer 1

[Ameer Hamza]

Check this:

alpha=0.1; % alpha is 0.1
Wcr=10;
w1=logspace(-1,log10(Wcr),1000);
w2=logspace(log10(Wcr),3,1000); 
Mag1=20*alpha*ones(1,numel(w1)); %<---- you need to multiply alpha here too
Mag2=@(w2) 20*alpha*log10(w2);
semilogx(w1,Mag1);
hold on;
semilogx(w2,Mag2(w2));
grid on;
xlabel('Frequency');
ylabel('dB')

Also try this to plot all values from 0.1 to 0.9 on one graph

Wcr=10;
w1=logspace(-1,log10(Wcr),1000);
w2=logspace(log10(Wcr),3,1000); 

ax = axes('XScale', 'log');
hold on;
Alpha=0.1:0.1:0.9;
for i=1:numel(Alpha)
    alpha = Alpha(i);
    Mag1=20*alpha*ones(1,numel(w1));
    Mag2=@(w2) 20*alpha*log10(w2);
    semilogx(w1,Mag1);
    semilogx(w2,Mag2(w2));
end

grid on;
xlabel('Frequency');
ylabel('dB');