In modern commercial products, a carrier frequency of 38 KHz is used when sending data command signals to the infrared IR receiver. The IR receiver then decodes the signal to understand and execute the command.
Purpose & Overview of this project
The purposes of this tutorial is to create an infrared IR receiver that receives data commands from a Direct TV remote control. The IR receiver should then decode the command and execute it. Most commands will be something simple like writing to an LCD display, to verify that the system works.
This tutorial is meant to build a working IR receiver system, not to 'knock your socks off' with some brand new technology. So keep that in mind as you're reading. The parts needed to complete this tutorial are all relatively low cost: resistors, op-amps and diodes.