Mean Foundamental frequency and periodic impulse train generation

Hello Guys ,

I am trying to estimate the mean foundamental frequency of a vowel segment and then use it to generate an impulse train and i can't do it . It is useful to notice that Fs=24000(sampling frequency) , NBITS=16(number of bits per sample),unit amplitude , 1 sample in width and 1 second time!Can you please help me?

Thanks in advance Sifo