Since you have the waveform in squarewave form, it should be easy to convert to logic level. Then send this to a settable digital delay to adjust the phase.

Ten years ago I programmed a Xilinx Field Programmable Gate Array (FPGA) to variably delay the phase of a 2400 Hz tone 0-180 degrees with 1 degree resolution. Very precise and repeatable. A microcontroller or DSP could do this too, or use a tapped digital delay line.

If you must stay analog, try a Phase Locked Loop (PLL) IC.

Good luck!

Kevin VanZuilen "KevinVZ"

Suggestion: Visit
http://www.planetee.com/planetee/servlet/DisplayDocument?ArticleID=389
http://www.mathworks.com/access/helpdesk/help/toolbox/commblks/simref12.shtml
http://www.mathworks.com/access/helpdesk/help/toolbox/commblks/simref12.shtml#611854
http://www.mathworks.com/access/helpdesk/help/toolbox/commblks/mfskdemodulatorbaseband.shtml#436894
http://nmsp.gsfc.nasa.gov/tdrss/mod.html
http://www.physics.udel.edu/wwwusers/watson/student_projects/scen167/thosguys/psk.html
http://www.kender.es/~edu/psk31.html
http://www.ac6v.com/opmodes.htm#PSK31
http://www.cs.ucl.ac.uk/staff/S.Bhatti/D51-notes/node12.html
http://www.delphion.com/patlist?&xcl=375&ea=1
(above include various related patents)
Demodulation aspects:
http://www.mathworks.com/access/helpdesk/help/toolbox/comm/ddemod.shtml
http://www.ednmag.com/ednmag/reg/2000/06222000/designideas.htm
http://www.uspto.gov/web/offices/ac/ido/oeip/taf/def/329.htm
for more info and specifics to your task. It appears that more info is needed whether your square wave is supposed to be phase shift self-correcting or phase shift compensating for a phase shift keyed message phase 0-180° phase variations and how fast variations. The phase shift may vary in time.