【摘要】 采用TSMC 0.18μm RF CMOS工艺,设计了一种Nauta跨导的Gm_C复数带通滤波器调谐电路,可实现滤波器的频率和Q值同时调谐.该调谐电路的频率调谐环路使用数字鉴频器和改进结构的数模转换器,Q值调谐电路采用能够在高输出电压下准确镜像电流的电流镜,整个调谐电路具备有利于改善滤波器线性度的高调谐电压输出能力.测试结果表明,1.8 V电源电压下,调谐电路输出的调谐电压最高可达到1.71 V.调谐后滤波器的中心频率和带宽偏差降到小于3%.更多还原

【Abstract】 A tuning circuit is designed and implemented on 0.18 μm RF CMOS process.It can simultaneously tune center frequency and Q factor of a Gm-C complex band-pass filter built with Nauta’s transconductor.The digital frequency detector and the improved frame’s DAC are applied in the frequency tuning loop of the tuning circuit,and the current mirror which can mirror accurately current under the condition of high output voltage is adopted in the Q tuning circuit.Thus the tuning circuit has capability of supplying the high tuning voltage,which is helpful for improving the filter’s linearity.Test results show that output tuning voltage of the tuning circuit can be up to 1.71 V at 1.8 V supply voltage.After the filter is tuned,the error of its center frequency and bandwidth is decreased to less than 3%.更多还原