針對傳遞函數描述的模擬濾波器頻率響應具有上凸尖峰的問題，引入微波網絡理論，考察插入衰減這一工作特性參量，分析各自的物理意義，比較了傳遞函數與插入衰減的異同點，并推導了兩者的轉換關系式。計算和仿真首先由插入衰減得到了標準的濾波器頻率響應，利用轉換關系式可以從插入衰減得出傳遞函數的頻率響應。結果分析表明，對于模擬濾波器，插入衰減描述其頻率響應更準確;而對于數字濾波器，插入衰減和傳遞函數的概念是一致的，都可以得到標準的頻率響應。

　　Abstract:

　　Aiming at the problem that there exists convex peak in the frequency response of analog filter showed by transfer function， the paper introduced microwave network theory，and investigated insert attenuation which is a characteristics parameter. Then the paper compared the similarities and differences between insertion attenuation and transfer function based on the analysis of physical significance of them， and got the conversion relational expression with each other. The paper got the standard frequency response through calculating and emulating insert attenuation, then derived the frequency response of transfer function from the conversion relational expression. The results show that insert attenuation is more accurate to describe the frequency response of analog filter， while insert attenuation and transfer function are accordant to digital filter， both can get the standard frequency response.