可不可以把滤波器的带内增益平坦度做成可以调节的啊？

为了调节整个电路的增益平坦度，根据电路的增益平坦度特性，做一个滤波器，该滤波器的增益平坦度特性和未加滤波器的电路增益平坦度特性正好相反，这样连在一起后整个电路的平坦度就会很好。但我认为要是电路的平坦度不是很差或者变化是单调的，滤波器比较容易补偿，但若电路的平坦度比较的没规则，是不是滤波器也不好做啊（故意做平坦难，故意设计成某一个形式的平坦度是不是也很难啊），那位大侠做过这方面的啊，谢谢

Actually not need to design a filter specially for gain flatness compensation unless you mean to filtering other spurious signals. And it is very likely to have problems when you connect such filters with the rest of the circuits because of the matching problems of the filters.
We can use some simple networks to compensate simple inband flatness problems, such as single rise, down, dip...
For complicated flatness problems, it is not suggested to design such networks, because it is very likely the flatness is different from module to module. so one circuits good for this board may not work with the other one.

除了利用filiter
还有没有其他办法提高电路的flatness呢?

My experience told me that reducing the Q factor of the whole circuit can be helpful in obtain better flatness, which means more resistive components are needed;
a circuit with very high Q is more likely to have flatness problem; some times, oscillation happens; And this cause big trouble;
certainly reducing Q will lead to less gain and higher NF; And in some situations, this is not allowed; in such cases, you need to carefully design the circuit with perfect gain, flatness and matching;

有点不容易！用ADS或者其他工具可以仿真，可以实现！这几天做了一个LNA。BW=1GHz平坦度可以做到《0.6dB.Gain>23dB

部分预失真技术，但是我没有做过
这个调整是比较有限的，可以在其他的部分做或许比filter更容易些

单调的平坦度或者抛物线型的增益曲线可以由均衡电路来实现
就是在电路中是并上（电阻与（电感电容并联）串联）来调节

可是一般的平坦度不是单调的或抛物线型的，若平坦度不是很差可以通过可调滤波器调节出来的。

小编说的只是一种方法，还可以调整放大器啊，混频器电路（如果有的话）。