Making Bode Plots with GUI in MATLAB

[DianeS]

Hello guys! I have an issue, I'm trying to make a program in which you can get a bode plot by knowing the transfer function in guide. The basic idea is this: you enter 4 numbers in the interface and by those numbers you can know the transfer function, basically I'm doing this as a final step:

a = get(handles.T1_editText,'String');
b = get(handles.T2_editText,'String');
c = get(handles.T3_editText,'String');
d = get(handles.T4_editText,'String');
num=[a*b,a+b,1];
den=[c*d,c+d,1];
sys=tf(num,den);
bode(sys)
guidata(hObject, handles);

I know there is something wrong with it, because I'm not getting the same plots i get in MATLAB to check the results (i write the transfer function in numbers). And another problem i have is that When i enter certain values I don't even get a plot and i get this message:

? Error using ==> mtimes
Inner matrix dimensions must agree.

Error in ==> lol>Grafica_pushbutton_Callback at 213
num=[a*b,b+a,1];

Error in ==> gui_mainfcn at 96
feval(varargin{:});

Error in ==> lol at 42
gui_mainfcn(gui_State, varargin{:});

Error in ==> @(hObject,eventdata)lol('Grafica_pushbutton_Callback',hObject,eventdata,guidata(hObject))


? Error while evaluating uicontrol Callback

Which doesn't happen with different values.
Oh and one more thing, when i get do get the plot, it's all over my GUI screen, and i can't even see, is there a way to plot it in a different window by using a command?

I'll put up some images of what I'm talking about so you have a better idea.

I'm kinda new to this MATLAB stuff, so try to bare with me :)
Thanks in advance for your answers.

 

[mmwave]

Hello there! It seems like you are facing some issues with your code and getting the desired results. I can offer some suggestions that might help you solve your problems.

Firstly, it is important to understand the error message you are getting. The "Inner matrix dimensions must agree" error occurs when you are trying to multiply two matrices with incompatible dimensions. In your code, you are trying to multiply two strings (a and b) which is not a valid operation. To fix this, you can convert the strings to numbers using the str2double() function. For example, a = str2double(get(handles.T1_editText,'String')); This will convert the string to a number and then you can perform the multiplication operation.

Secondly, it is important to check the values you are entering in the interface. If you are getting an error with certain values, it could mean that those values are causing the error. Make sure to enter valid values for the transfer function.

Regarding your question about plotting in a separate window, you can use the figure() function to create a new figure window and then use the bodeplot() function to plot your transfer function in that window. For example, figure(); bodeplot(sys); This will create a new figure window and plot your transfer function in it.

I hope these suggestions will help you solve your problems. Good luck with your program! Let me know if you need any further assistance.