| 摘要: |
| 通过分析频域的契比雪夫滤波函数特性和时域的贝塞尔滤波函数特性，采用计算机仿
真手段，在这两种函数之间寻找到最佳折衷办法，再在实践中进行验证，平衡了窄
带晶体滤波器中频域和时域这一对矛盾，使得滤波器的群时延波动从5 μs降到最小只
有0.3 μs，实现了窄带晶体滤波器通带内具有近似恒定群时延的特性，降低了整机和
系统出现误
码、乱码的几率，确保了输出信号的纯度。 |
| 关键词: 晶体滤波器；窄带 小群时延波动 高衰减 |
| DOI：10.3969/j.issn.1001-893X. |
|
| 基金项目: |
|
| Design of Narrowband Little Ripple Groupdelay Crystal Filter |
| JIANG Shan |
| (Chengdu Spaceon Electronics Co., Ltd., Chengdu 611731,China) |
| Abstract: |
| A narrowband crystal filter design methodology wit
h little ripple groupdelay is presented. Through computer simulation, the chara
ct
eristics of Chebyshev function in the frequency domain and the ones of Bessel fu
nction in the time domain are analyzed, and a function with the best tra
deoff betwee
n Chebyshev and Bessel is chosen. This method is benchmarked in several industry
cases, de
monstrating its ability to balance the conflicts in the frequency domain and tim
e domain, and to reduce the ripple groupdelay from 5μs to 03μs. It is proved
th
at this design maintains almost constant groupdelay within the whole narrowb
and filter bandwidth,thus reducing the system error probability and ensuring pur
e output signals. |
| Key words: crystal filter narrowband little ripple groupdelay high attenuation |
《电讯技术》编辑部 