摘要
对频率在较宽范围内变化的信号进行滤波,需要滤波器能灵活地变换通带,同时,为尽可能抑制输入信号中的带外噪声和失真,要求截止频率准确、稳定。本文根据SCF(Switched Capacitor Filter——开关电容滤波器)对截止频率控制精确,频率响应特性可大范围调节的特点,提出了以MAX7418-MAX7425系列SCF为核心器件,以可编程逻辑器件EPM7128S为可控时钟源的程控低通滤波电路设计方法。电路实现了对滤波截止频率精确控制以及对频率响应特性的大范围程控调节,并能方便地扩展至多个滤波通道。
To filter signals that frequency varies in a vast range, the filter should change its frequency response flexibly, and to try to suppress the noise and distortion of the input signal out of band, corner frequency should be correct and stable. As the precise control of corner frequency and vast frequency-response adjustable range of SCF （ Switched Capacitor Filter ）, the paper bring forward a kind of filter circuit based-on SCFs MAX7418-MAX7425, using CPLD （complex programmable logic device） EPM7128S as programmable clock source. Such circuit reaches precise control of corner frequency and convenient control of frequency response in a vast frequency range, and can be easily extended to more filter channels.
出处
《电子测试》
2009年第11期9-12,共4页
Electronic Test
