Plotting using surf

Hello i am trying to do this, capture audio signal using analoginput then plotting the spectrogram in realtime. this is what i have so far:

    daq_object = analoginput('winsound');
    chan = addchannel(daq_object,[1 2]);
    x=[10];
    num_samples = 1000;
    axes(handles.axes1);
    plot_handle=surf(T,F,10*log10(P),'edgecolor','none'); 
    axis tight; 
    view(0,90);
    xlabel('Time (Seconds)'); ylabel('Hz');

   set(daq_object,'SamplesPerTrigger',inf,'SamplesAcquiredFcnCount',num_samples,...
        'SamplesAcquiredFcn',{@update_plot,handles});

function update_plot(handles)

    data = getdata(daq_object,num_samples);
    [S,F,T,P] = spectrogram(data(:,1),256,250,256,1E3);

        set(plot_handle,'YData',T,F,P);

end

i have few problems, first off all, initally i have this:

plot_handle=surf(T,F,10*log10(P),'edgecolor','none');

but i need to define T,F,and P.. but the problem is i don't have the audio sample yet. [since it will be in the GUI, when they press start the object will start, so audio will be started to collect].

also when i set the data,

set(plot_handle,'YData',T,F,P);
is this valid, sine the surf, function needs, T,F and P.

i am really confused, please help.

what i am trying to do is to have a real time spectrogram.

Answer 1

[Walter Roberson]

You cannot achieve what you want by setting YData. See my Answer in your earlier Question as to what the YData has to be updated to contain,

http://www.mathworks.com/matlabcentral/answers/12229-set-ydata-in-matlab-how-does-it-work

[rave]

i quite don't understand how you explained it, if you have time can you elaborate more on it. here i am only going to plot one channel, and it is a vector. i really don't understand what you explained in the topic "Set Ydata in matlab". sorry to be any inconvenience

[rave]

if you can show an example that would be great. please :(

[Walter Roberson]

You need to read the reference information about what YData is.

http://www.mathworks.com/help/techdoc/ref/lineseriesproperties.html

[rave]

I tired this: set(plot_handle,'XData',T,'YData',F,'ZData',P);

still error;