Phase Modulator-Demodulator

Hi,

I need to do a Phase Modulator-Demodulator, but I didn't find any circuit. How can I do this? I have no idea. Someone could help me?

Google phase modulator circuits

I've done this, but the circuits that I thought always missing information from any component and does not say how it calculates.

I have a ckt of phase shift modulator....
do u need it??
I also m desinging AM Modulatorby using {{IC (mc1496) and phase shift modulator and then Tuneable Bandpass filter and then Practical Envelop detector and in the end a low pass filter}} to get back the origional signal.