Abstract: A universal remote control transmitter for use with garage door openers including a number of switches whereby a user can program a transmitted modulation format and carrier frequency, and a controller for scanning the switches to determine the user programmed selections. The controller, in response to the programmed selections, outputs the required modulation to a selected transmitter, as well as direction to fine tune the transmitter to the particular carrier frequency. Also included is a power sensor circuit that responds to a change in power supply voltage by adjusting the modulation to maintain a constant peak transmitter output power.

Abstract: A universal remote control transmitter for use with garage door openers including a number of switches whereby a user can program a transmitted modulation format and carrier frequency, and a controller for scanning the switches to determine the user programmed selections. The controller, in response to the programmed selections, outputs the required modulation to a selected transmitter, as well as direction to fine tune the transmitter to the particular carrier frequency. Also included is a power sensor circuit that responds to a change in power supply voltage by adjusting the modulation to maintain a constant peak transmitter output power.