| 摘要 |
PURPOSE:To control a wide dynamic range by controlling the output voltage of a power amplifier corresponding to the compared difference between the output of the power amplifier and a prescribed reference voltage, adjusting gain and connecting one of them to the power amplifier. CONSTITUTION:A part of the power of the RF transmission output of the power amplifier 1 is taken out and detected by a detection circuit 2 and compared with a reference control voltage outputted from a DA converter 3 at a comparator circuit 4. The circuit 4 lowers an APC voltage when the detected voltage > the control voltage. In this case, the optimum gain is adjusted in output ranges for respectively operating the comparator circuits 4 and 6. Then, the comparator circuits are switched and selected by switches 7 and 8 or the switches 9 and 10 by switch control signals and control with less errors is made possible even when the dynamic range is wide for the transmission output of the power amplifier 1. |
