Emitter/receiver for frequency detection

Hi,

I need to work on a small system like this:

Part 1) Emitter: This one I call "frequency emitter" (not sure the correct name). It's supposed to continuously send a 1.632Khz signal (no modulation needed) through an antenna.

Part 2) Receiver: Its job is just detect the presence or absence of the 1.632Khz signal.

The system has to be able to cover areas like hallway or supermarket aisle and thus be able to adjust the emitter power.

I would appreciate very much if someone could give me some hints (block diagram, app. notes, etc.) on how to go for it.

Regards,

Ric