How to detect time of arousal with excitation signal in speech signal? I have several seconds of speech signal and I have to detect moments in time of arousal with excitation signal, which is creating by larynx. I'm looking for useful reference since several days. I know that a speech signal is a convolution of excitation signal with a filter response and I've read about cepstral analysis and linear prediction, but I still do not know how to take advantage of these methods for my puspose. I think that I have to separate these two signals in some way.

I found the fundamental frequency by create autocorelation function and reading maxima, which gave me the period of fundamental tone. But actualy I don't know how to use it.
I need to do it in matlab. Please help me.

Here is good example what I need.
http://www.iba.zut.edu.pl/dydaktyka/pliki/referat_js/image002.jpg
In the top plot these impulses are marked as short lines and this is what I need to do.
You are looking for the instants of glottal closure, or GCIs.  There are many freely Matlab algorithms to do such.  Check out, for example, the DYPSA algorithm.  A paper explaining how these algorithms generally work can be found here.