题目/Title：一种4MHz复数滤波器及其自动调谐系统的设计
                        Design of a 4 MHz Complex Filter with Automatic Tuning System

作者/Author：杜定坤,李永明,王志华,Seeteck Tan
                        Dingkun Du,Yongming Li,Zhihua Wang,Seeteck Tan

期刊/Journal：微电子学 Microelectronics

年份/Issue Date：2006

卷（期）及页码/Volume（No.）&pages：Vol.36, No.6, pp. 820 - 824

摘要/Abstract：
介绍了一种基于蛙跳式低通滤波器原型综合而成的复数滤波器。该电路具有较低的灵敏度，从而提高了稳定性。滤波器的自动调谐系统具有设计简单、精度易控制等特点，并可在调谐完成后关闭，减少了功耗以及与滤波器的互扰。电路采用0．18μm CMOS工艺设计，滤波器的中心频率为4MHz，带宽为2MHz，增益约为0dB，可达到约53dB的镜像抑制比，调谐精度可以控制在3%左右，功耗为7．5mW。
A complex filter synthesized from the leapfrog lowpass prototype is proposed. The filter has low sensitivity and, therefore, an improved stability. The tuning system, which is easy to design and well controlled, can be turned off on the completion of tuning, which reduces power consumption and interference with the filter. Implemented in 0. 18 μm CMOS process, the filter is centered at 4 MHz with a bandwidth of 2 MHz and a voltage gain of about 0 dB. The image rejection ratio of the filter is up to 53 dB and its tuning accuracy is about 3%. The device consumes 7.5 mW of Dower.