I need to implement an algorithm for automatic modulation recognition using matlab. I am planning to do this by using pattern recognition, I have read about the decision tree approach, it says to "ideniify the constant envelope signals (CW, FM, FSK). PSK sigals are

not considered as constant envelope signals, since in practice

they are band-limited, which leads to a non-constant

envelope. The feature used to identify the envelope variations

is the maximum of the squared Fourier transform of the

normalized signal amplitudes "

How can i implement this technique in matlab, i need help with the code. I also need to calculate the instantaneous freq/phase, etc. I am using a .wav file.