| 摘要 |
PURPOSE: A smart key transmitter and a transmission output control method thereof are provided to control transmission output by changing a matching value of an antenna. CONSTITUTION: A center processing unit(110) outputs a transmission signal indicating the execution of a function. The center processing unit output a control signal for controlling the size of transmission output. An applied power control circuit(170) outputs power corresponding to the control signal. A varactor diode(D1) is a part of a matching circuit in an antenna. The varactor diode changes the matching value of the antenna with a capacitance according to the power. The varactor diode controls the size of the transmission output. [Reference numerals] (110) Center processing unit; (130) Colpitts circuit; (140) First matching circuit; (160) Varactor diode; (AA,BB) 3V(Battery voltage); (CC) SAW resonator |
