| 摘要 |
PURPOSE:To exclude the transient response at the transmission start in an APC circuit (automatic output control circuit) by inserting a time constant circuit to a power line supplied to a power amplifier of a transmitter via the APC circuit. CONSTITUTION:In supplying a power to a pre-stage power amplifier 1 via the APC 4, the power is supplied via a semiconductor switch circuit 5 and the circuit 5 is controlled by a transmission start signal PTT through a time constant circuit 6. Thus, even when the signal PTT is inputted to the APC circuit 14, the start voltage to a switch circuit 5 rises slowly corresponding to the said time constant. Thus, the output of the power amplifier 1 increases gradually, and reaches an antenna filter via a final stage power amplifier 2 and the part is inputted to the APC via a rectifier 3. Thus, after a control voltage is applied to the APC 4 and the voltage control function of the APC is acted, the output voltage of the circuit 6 is saturated and the normal power voltage is applied to the amplifier 1.
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