Change bode frequency units with idfrd data

Hello,

I have a problem to change the frequency units of my bode plot. I am using the function iddata in order to convert the time series data. After I am using the etfe function in order to change the iddata into a function transfer. I am trying to plot the bode with the frequency units in Hz but it odes not work, it stays in rad/s.

Here is the sample code :

DATA = iddata(y, x, 0.001); %x is the input data and y the output
G = etfe(DATA,[],15001); %G is a idfrd data qnd 15001 is the data number
G = chgunits(G,'Hz'); %change units of the transfer function to see if it
%affects the bodeplot
P = bodeoptions;
P.FreqUnits = 'Hz'; %set the bode options frequency units in Hz
bode(G,P); %Try using bodeplot instead but get the same results

Thank you in advance, it would be very helpful if someone could help on this issue.

Answer 1

[Arkadiy Turevskiy]

G = chgunits(G,'Hz')

does it for me in R2013a.

You can also right click on the bode plot, Properties, Units, and set units there.

If none of this work, we would need to know the version number of MATLAB you are using. You can also submit a help request here.

Arkadiy

Answer 2

[Christophe]

Thank you for your answer, I think it was a version problem, I was using 2007b.