Multi-frequency radio frequency transmitter with code learning capability

Abstract

A radio frequency transmitter for use in generating coded commands learned from received coded radio frequency signals. An transceiver circuit including a switching element and a tunable filter tuning element is coupled to a programmable controller, e.g, a microprocessor. The programmable controller operates the switching element of said transceiver circuit in either a first or a second mode for receiving or transmitting coded radio frequency signals, respectively via an antenna coupled to the tuning element. The switching element is operable in the first mode to demodulate received coded radio frequency signals, and the programmable controller learns the received coded radio frequency signals and stores coded commands in memory. In the second mode of operation, an oscillator is modulated by generated coded signals from the programmable controller using the stored coded commands from memory. The generation of plural coded radio frequency commands with the single radio frequency transmitter unit facilitates the learning, responsive to a received radio frequency signal, of an additional coded radio frequency command for additional door and gate operators.