Patent ID: 7469129
Filing Date: 2008-12-23
Classification: E05F,E05Y,G07C,G08C

Abstract:
1. A method of transmitting a device activation signal for remotely actuating a device, the device activation signal having an RF carrier frequency and a power level, comprising the steps of: providing a transmission antenna assembly having a tunable impedance; generating the RF carrier frequency; generating an antenna assembly tuning signal for controlling the antenna assembly impedance; transmitting the device activation signal at the RF carrier frequency; detecting the device activation signal power level; and adjusting the antenna assembly tuning signal in response to the detected activation signal power level; determining a target detector voltage based on a stored starting point transmission power value associated with stored characteristics of the device activation signal; and comparing the detected activation signal power level to the target detector voltage; wherein adjusting the antenna assembly tuning signal in response to the detected activation signal comprises adjusting the antenna assembly tuning signal such that the antenna assembly tuning signal is calculated to result in a detector voltage approximately corresponding to the target detector voltage.