基于功率检测自适应的前馈功放设计

分析了常用双环自适应前馈电路在屏蔽和宽带频率兼顾等地方的缺陷，设计了一个功率检测自适应电路。功率检测自适应应用于前馈系统第一极环路，通过MCU监控电压检测值，自动调节第一环路的移相、调幅矢量调节器，改变相位、幅度参数，以达到环路抵消最好，保证在功率与频率不断变化的情况下，误差信号提取时刻都保持最纯净。仿真结果显示，在输出125W的GSM前馈系统中，可使其IMD3小于-65dBc。

Design of adaptive feed-forward power amplifier based on power detection

The defects at some places in common double-loop adaptive feed-forward circuit where the shielding and broadband frequency are considered are analyse.An adaptive circuit for power detection are design.The adaptive circuit for power detection is used in the first polar loop.With MCU,the voltage detection value is monitored,the first loop phase and amplitude vector adjuster are regulated automatically,and the phase and amplitude parameters are changed automatically to achieve the best loop offset and to ensure the most pure of the error signal in the extraction time under the continuous changing condition of power and frequency.The simulation results show that the IMD3 of the feedforward system is less than ―65 dBc in the GSM feedforward system whose output is 125 W.