| 摘要 |
Attenuating signal power levels of RF signals, e.g. for a universal garage door opener (UGDO), remote keyless entry <B>(RKE)</B> unit, tyre pressure monitor and/or a passive entry element. The attenuation of the RF signals is achieved with pulse-width modulation (PWM) control, preferably as a function of transmission frequencies and/or data protocols. In one embodiment, a desired output power level is ascertained 54 based upon a determined programming code 52, which may specify a UGDO vendor or may be determined as a function of inputs received by a vehicle system controller. A PWM duty cycle is subsequently determined 58 to ensure that an input power level 56 is sufficiently attenuated 60 to achieve the desired output power level 54. Thus, appropriate output power levels for particular transmission frequencies and data protocols may be determined in line with FCC regulations. |
