基于开关电容滤波器LTC1064的BPF设计  

Design of the band pass filter based on switched capacitor filter LTC1064

作　　者：韩警[1] 陈星[1] 窦垭锡[1] 

机构地区：[1]北京航空航天大学电子信息工程学院,北京100191

出　　处：《电子测量技术》2013年第8期19-23,共5页Electronic Measurement Technology

摘　　要：介绍了一种在2kHz固定带宽条件下,中心频率可在0.5～100kHz范围内调节的8阶椭圆带通滤波器的设计方法,采用2片LTC1064开关电容滤波器模块分别构成8阶椭圆高通和低通滤波器,然后两者级联构成带通滤波器,利用FPGA生成2路频率可控的时钟信号作为LTC1064的时钟输入,分别调节高通和低通滤波器的截止频率,从而实现带通滤波器的中心频率可调节,最后针对开关电容滤波器的直流偏移和时钟馈通问题进行后置滤波电路的设计。spice模型仿真结果表明,此带通滤波器的各项指标均达到了设计要求。This paper describes a method to design a 8-order elliptic band pass filter with the 2kHz fixed bandwidth and the center frequency of this band pass filter can be adjusted within the range from 0.5kHz to 100kHz.Two switched capacitor filters LTC1064are used to design the 8-order elliptic high pass filter and 8-order elliptic low pass filter respectively.The band pass filter is formed by cascaded the high pass and low pass filters.FPGA is used to generate two frequency tunable clock signals which are used as clock input of the two LTC1064respectively.At last,in view of the DC offset and clock feed through problems of switched capacitor filter,a rear filter circuit is designed.The spice model simulation results show that,all the indicators of this band pass filter have reached the design requirements.

关 键 词：开关电容滤波器 带通滤波器 直接数字频率合成 程控滤波器 

分 类 号：TN713[电子电信—电路与系统]