針對傳遞函數(shù)描述的模擬濾波器頻率響應(yīng)具有上凸尖峰的問題，引入微波網(wǎng)絡(luò)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(shù)與插入衰減的異同點(diǎn)，并推導(dǎo)了兩者的轉(zhuǎn)換關(guān)系式。計算和仿真首先由插入衰減得到了標(biāo)準(zhǔn)的濾波器頻率響應(yīng)，利用轉(zhuǎn)換關(guān)系式可以從插入衰減得出傳遞函數(shù)的頻率響應(yīng)。結(jié)果分析表明，對于模擬濾波器，插入衰減描述其頻率響應(yīng)更準(zhǔn)確;而對于數(shù)字濾波器，插入衰減和傳遞函數(shù)的概念是一致的，都可以得到標(biāo)準(zhǔn)的頻率響應(yīng)。

　　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.