You do not need to modulate data as you would with IR when using RF. The carrier ON/OFF
is controlled by the logic input on the RF transmitter.

With the transmitter data input at ground you suppress the carrier. When the data input is
logic 1 the carrier is ON. All you're really doing is turning the RF carrier ON/OFF by toggling
the transmitter data input.

On this transmitter you're controlling a SAW resonator that creates the RF carrier.

This project http://www.rentron.com/Stamp_RF.htm is one very simple example. And
Dave Houston has several more advanced examples here you can find with a search.

Have a look at this http://www.linxtechnologies.com/Docu...datastruct.pdf for
an example of what a commercial encoder IC data structure looks like.