| 摘要 |
PURPOSE:To enable the automatic power control function to double the transmission power lowering function for the mobile radio communication by varying the feedback quantity of the system via the DC detection signal of the automatic power control system, and thus to realize a miniature transmitter with the low power consumption as well as the steady transmission power. CONSTITUTION:The output of transmission power level detector 4 is applied to detection voltage adjuster circuit 5 and 5', and the output of switch 11 and 11' at the output side is supplied to control comparator 6. When circuit 5 features a higher setting voltage than circuit 5', the comparison error signal compared with the power control reference voltage at comparator 6 becomes larger for circuit 5 than 5'. And the bias power voltage which is supplied to power amplifier 2 via bias voltage controller 7 is lowered, and the transmission power to be supplied to antenna 10 becomes lower when switch 11 is turned on than when switch 11' is turned on. The automatic power supply is given even in case either one of switch 11 and 11' is on. |
