Putting transfer function expression in the title of a bode plot

Hi

I am trying to put a transfer function expression in the title of a bode plot.

This code worked in 2010b.

I am now using R2019a so this is the version my question applies to.

the code:

num=[1 2];

den=[1 7 49];

trans=tf(num,den);

syms s

n = sym(num);

d = sym(den);

ns = poly2sym(n,s);

ds = poly2sym(d,s);

tfsym = ns/ds;

tftitle = latex(tfsym);

figure(1)

bode(trans)

title(sprintf('Bode plot of: $$ %s $$', tftitle), 'Interpreter','latex')

It works but gives the following warnings:

String scalar or character vector must have valid interpreter syntax:

Bode plot of: $$ \frac{1}{s^2+2\,s+1} $$

> In defaulterrorcallback (line 12)

In ctrluis.axesgrid/labelpos (line 26)

In ctrluis.axesgrid/setlabels (line 83)

In ctrluis.axesgroup/addbypass>localTitle (line 24)

In mwbypass (line 17)

In title (line 49)

In bode (line 22)

Anyone any ideas?

Thank you

tgahan

[Aviel Moos]

Did you try to use: Bodeoptions ?

Answer 1

[Subhadeep Koley]

MATLAB provides bodeoptions to add various parameters to your bode plot.

The following code may help you.

tfsym = ns/ds;
tftitle = latex(tfsym);
figure(1)
opts=bodeoptions;
opts.Title.Interpreter = 'latex';
opts.Title.FontSize = 12;
opts.XLabel.FontSize = 12;
opts.YLabel.FontSize = 12;
opts.Title.String = sprintf('Bode plot of: $$ %s $$', tftitle);
bodeplot(trans,opts);

[Thomas Gahan]

Apologies for the late reply, was on vacation.

Thank you very much for your expert assistance.

This worked perfect.

Kind regards

tgahan