三阶级联复数有源RC带通滤波器

A THIRD ORDER CASCADED ACTIVE RC COMPLEX BAND PASS FILTER

采用0.18μmCMOS工艺设计了一款应用在无线传网中的三阶级联有源RC复数带通滤波器,同时设计了自动频率调谐电路(AFT)。该滤波器采用的是切比雪夫逼近函数予以实现。在5比特数字控制码开关电容阵列的控制下,AFT电路即可完成对主体滤波器电路频率变化的校正。仿真结果显示,滤波器的中心频率稳定在2MHz,通带带宽为2MHz,镜像抑制比大于34dB,相邻信道阻带衰减大于34dB,通带纹波小于1dB,消耗电流为2.3mA,工作电源电压为1.8V。

A third order cascaded active RC complex band pass filter （BPF） with automatic frequency tuning （ AFT ） for WSN applications is designed using 0.18 μm RF CMOS process. The filter is implemented in Chebyshev biquad structure. The AFT circuit is introduced to calibrate the frequency variation by a 5-bit switched-capacitor array. Simulation results indicate that the filter bandwidth is 2MHz and is centered at 2MHz. The image rejection ratio （ IRR ） is greater than 34dB around -2MHz and the adjacent channel rejection （ ACR ） around 6MHz is also higher than 34dB while the ripple in the passband is less than ldB. The filter consumes 2.3mA under 1.8V power supply.