3G、4G 功率校准时，power detector coupler loss校准的到底是什么？求大神答疑解惑！

3G、4G 功率校准时，power detector coupler loss校准的到底是什么?求大神答疑解惑！
VGA DAC, PA high mode=296,198
VGA DAC, PA middle mode=238,198
VGA DAC, PA low mode=161,198
Tx compensation power detector coupler loss high=-23.5938
Tx compensation power detector coupler loss low=-23.1875
Tx compensation power detector coupler loss middle=-23.2812

同求！

类似PA gain 那个值 TRC会有一个接受到的目标值，当耦合功率过大 （输出功率大）会增大loss 绝对值，降低输出功率 ，都是一个欺骗TRC的过程

大神 你好 ！
关于MTK的 3G 4G的 POWER DETECTOR ，小弟有问题请教下：
1.INI文件里 LTE的TPC部分 有给出coupler loss值
Tx compensation power detector coupler loss high=-24.65625
Tx compensation power detector coupler loss low=-24.71875
Tx compensation power detector coupler loss middle=-24.65625
也有各信道对应高，中，低增益模式下对应的补偿值
Tx compensation power detector pa high temperature 1=0.062500,0.062500,0.031250,0.062500,0.093750,0.093750,0.062500,0.093750,0.156250,0.156250,0.125000,0.093750,0.093750,0.093750,0.093750,0.093750,0.093750,0.093750,0.093750,0.093750,0.093750

这两个在进入非信令模式后都有对应。

问题是：
进行非信令调试时，一般先选择中间信道，改变coupler loss值，达到期望功率， 其它信道，修改power detector 补偿值，使达到期望功率，看TX指标
1.这种方式实质改变的是收发器出来的功率，PA增益固定，进而改变PA的输出功率?
2.为什么不直接修改PA GAIN和PA GAIN在各个信道的补偿值?