摘要
濾波器的基本功能是從輸入信號中選出所需要的頻率成分,而把其它不需要的頻率成份濾除掉,有源濾波器廣泛用于通信和測量電路中,特別適用于工作在低頻和超低頻波段,最低頻率可延伸到1HZ 以下。
有源濾波器的設計先根據信號處理的要求得到一個實有理近似傳遞函數H( S),根據傳遞函數進行電路實現一般有兩種類型,即直接型和級鏈型, 直接型將H ( s) 作為一個整體來直接實現,級鏈型將H( s) 分解為一階和二階基本節函數來級鏈實現,在級鏈實現中,傳遞函數用若干個二階級或一階級濾波器的級鏈來實現,
有源濾波器從帶通性能看可分成低通濾波器(L PF),高通濾波器(HPF),帶通濾波器(BPF) 和帶阻濾波器(BEF) 等。利用計算機計算和繪制出大量優化圖表,查索圖表就可以迅速得到濾波器的元件參數和各種特性,設計出所要求的濾波器。
關鍵詞:有源濾波器,截止頻率,傳遞函數
Abstract
Filter's basic function is selects the frequency component needed which from the input signal,The other frequency components which is not needed is filtered out, APF is widely used in communications and measurement circuit, Particularly applicable to work in low-frequency and ultra-low-frequency band, the lowest frequency may extend to 1HZ below
The active filter's design obtains on signal processing requirements are a function H(s).According to a transfer function circuits are generally two types, a direct and chain type. Direct-to H (s) as a whole to realize direct, Another divided the H (s) into first and second order of a basic, In the level chain realizes, The transfer function realizes with several two social classes or a social class filter's level chain,
Active from the band-pass filter performance can be divided into low-pass filter (L PF), high-pass filter (HPF), Band-pass filter (BPF) and the band Filter (BEF), and so on,Using computer calculations and drawing a lot of optimization of charts, Check on the chart can quickly filter components of various parameters and characteristics, Designed to filter,
Keywords: APF, Cut-off frequency, Transfer Function