Minh,

I don't have any references to rf and an 89C2051, but here's a couple of references to rf transceivers using PIC micros. While this isn't a PIC forum, there is some good reading on the rf side applicable to any micro which may source a digital baseband datastream.

http://www.microchip.com/1010/supp.../index.htm

http://www.microchip.com/1010/supp.../index.htm

http://www.microchip.com/1010/supp.../index.htm

Enjoy,

Bruce