群时延精确设计的全差分四阶Bessel滤波器

Fully Differential 4th-order Bessel Filter Accurately Designed with Group Delay

采用MOS管有源电阻 ,提出了一种全差分R MOSFET C四阶Bessel有源低通滤波器 ,.通过调节工作于亚阈值区的CMOS管的沟道导纳补偿电阻值的大小 ,能抵消集成电路制造工艺中电阻值的一致偏差 ,实现Bessel有源滤波器群时延的精确设计 .根据无源滤波器的状态方程完成有源滤波器的综合 ,应用 3 3V ,0 5 μmCMOS工艺完成了群时延大小为 0 75 μs的四阶Bessel低通滤波器的管极计算机仿真 ,仿真结果表明所提电路正确有效 。

This paper presents a fully differential R-MOSFET-C 4th-order Bessel active low-pass filter with group delay adjusted by tuning the channel transconductance of CMOS transistors worked in weak inversion region. The tuning can counteract the deviation of resistor in the manufacture of integrated circuit, therefore the group delay of Bessel active filter can be designed and realized accurately. The active filter can be synthesized according to the state equation of passive filter. Computer simulation of 4th-order Bessel low-pass filter with 0.75 μm group delay indicate that the proposed circuits are both effective using 3.3 V 0.5 μm CMOS technology, and suitable for integration.