Similarly, we could design the demodulator of CPFSK
The following links will help you:
http://in.mathworks.com/help/comm/ref/cpfskdemodulatorbaseband.html
http://in.mathworks.com/help/comm/ref/comm.cpfskdemodulator-class.html
http://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=1011&context=ece_articles