common or conventional QPSK demodulator

[asraf]

hi there,

i would like to know the common technique used in QPSK demodulator? Thank you

 

[chuckey]

A phase locked local oscillator with a balanced mixer?
Frank

 

[asraf]

hai there,

first of all, thanks for your reply. but the things i would like to know is the common technique used in qpsk demodulator? whether maximum likelihood? or log likelihood? or just costas loop with LPF ? thanks in advance