HOW can I find Harmonicity and Pitch in the Audio signal

[ncomputing]

Hi
i am confusing about how can i find pitch or harmonicity in one signal with matlab
when find fundemental signal how can fine 2*f ,3*f,................,n*f
can anybody write matlab code for that ?
tnx so much

 

[chitturi_sb]

AMR-NB Encoder - File Exchange - MATLAB Central
check above link, one of my colleague did this. may help as amr codec also has a pitch finding module for speech