how to draw this kind of figure in matlab [1 Attachment]

I have a time signal, and if I calculate time-frequency spectra distribution, I'd like to draw a figure in which x axes is time, y axes ia frequency, like the figure in the attached file. does matlab provide a function to draw this kind of figure.
I am looking forward to seeing your answer.
yours sincerely
chen Start a New Thread

Chen-

> I have a time signal, and if I calculate time-frequency
> spectra distribution, I'd like to draw a figure in which
> x axes is time, y axes ia frequency, like the figure in
> the attached file. does matlab provide a function to draw
> this kind of figure.
> I am looking forward to seeing your answer.

Suggest to check out spectrogram() function. This link shows an example figure plot:

http://www.mathworks.com/access/helpdesk/help/toolbox/signal/spectrogram.html

And this link has some mention of gray-scale version:

http://www.mathworks.com/matlabcentral/fileexchange/1553

-Jeff Start a New Thread