一种基于Gm-C的高Q值模拟中频带通滤波器设计与实现

Design and Implementation of High Q Analog IF Bandpass Filter Based on Gm-C

摘要: 设计并实现了一种基于Gm-C二次节(Biquad)结构的6阶切比雪夫Ⅰ型模拟中频带通滤波器,中心频率为46MHz,带宽为2.046MHz.其中Biquad结构中加入了负阻抗单元,增加输出阻抗,实现滤波器的高Q值(品质因数).跨导放大器(Operational transconductance amplifier,OTA)单元使用源极负反馈技术,优化了OTA的线性性能.整个滤波器电路采用0.35μm CMOS工艺实现.经过仿真验证,滤波器的通带纹波是2.704dB,1.5倍带宽处衰减大于21dB.在3.3V电源电压情况下,滤波器的总电流消耗为8.87mA.

Abstract: A 46 MHz centre frequency, 2.046 MHz bandwidth 6th order Chebyshe-v-Ⅰbandpass integrated filter using a biquad Gm-C structure is designed and implemented.Negative resistance cells are used in the biquad structure to obtain high Q of the filter.The OTA has a high linearity with source degeneration technique using MOS resistors.The whole filter circuit is designed and simulated in 0.35 μm CMOS process.The pass-band ripple of the filter is 2.704 dB and the 1.5 bandwidth attenuation is higher than 21 dB.The total dc current consumption is 8.87 mA @ 3.3 V supply.