【作者】 饶中洋；

【导师】 滕建辅；

【作者基本信息】 天津大学 ， 信号与信息处理， 2004， 硕士

【摘要】 连续时间滤波器在各种通信和信号处理领域中有着广泛的应用，而全集成连续时间滤波器可以使整个系统更加稳定和可靠地工作。本论文对连续时间滤波器的设计进行了系统的研究，给出了三种全集成滤波器的设计方法。 首先，对于低频应用，可以使用 R-MOSFET-C 滤波器。它是由运算放大器构成的，但是其结构类似于有源 RC 滤波器。这些滤波器用标准的 CMOS 工艺实现，利用工作在线性区的 MOS 管来替代无源电阻。通过调节 MOS 管的栅极电压可以调节其等效的有源电阻，从而可以连续地调节滤波器的截止频率。文中提出了R-MOSFET-C 滤波器的一种设计方案，并给出了设计实例，该设计的仿真结果表明了它具有和有源 RC 滤波器相同的特性。 其次，对于应用频率较高的滤波器，介绍了新型元件运算跨导放大器 OTA，给出了它的模型以及应用原理，文中提出了一种 OTA 电路的设计，给出了电路参数，并且在此基础上，介绍了如何将无源 RLC 梯形滤波器转换成有源 OTA-C 滤波器。在给出的设计例子中，采用实际的 OTA，且对该实际的 OTA 的跨导进行了测试，最后的仿真结果表明，所设计的 OTA-C 滤波器满足设计要求，而且通过改变偏置电流可以使滤波器的截止频率连续地变化。 最后，对滤波器的调谐问题进行了研究。通过对多环反馈结构的详细讨论，介绍了 IFLF OTA-C 滤波器。由于元件值的不精确，需要对设计的滤波器进行调谐。调谐的方法可以分为两大类，一是直接调谐，二是间接调谐。本文给出了基于峰值调谐的设计方法，并且设计了一个五阶的 IFLF OTA-C 滤波器。最后的仿真结果表明 IFLF OTA-C 滤波器满足设计要求。更多还原

【Abstract】 Continuous-time filters are wilderly used in telecommuniation and signalprocessing systems. The system can be made to work more stable and reliable by usingfully-integrated continuous-time filters. This dissertation is concerned with the design offully integrated continuous-time filters. Three design methods are given. Firstly, in the lower frequency application, R-MOSFET-C filter is used. They areeasy to implemente with operational amplifier blocks while maintaining closearchitectural similarities to an active RC filter. These R-MOSFET-C filters,implemented in a standard CMOS process, utilize the linearized model behavior of anMOS transistor operating in the triode region instead of a passive resistor. Throughtuning the grid-voltage of MOS transistor, we can tune the equivalent resistance,accordingly tuning the cut-off frequency of the filter. A R-MOSFET-C filter designmethod is proposed and an example is presented in the dissertation. Simulation resultconfirms its performance similar to that of active RC filter. Secondly, for the high frequency application, a late-model device of operationaltransconductance amplifier is introduced. The design strategy of OTA is proposed andthe OTA parameters are given. Based on this design, the procedure of how to convert apassive RLC filter to active OTA-C filter is described. In the presented example, thedesigned OTA is used and the OTA’s transconductance is tested. Simulation resultshows that the OTA-C filter has same performance with RLC ladder filter. The cut-offfrequency of the filter is tuned by tuning its bias current. Finally, the tuning of the filter is studied and the multiple loop feedback topologyis discussed in detail. After the introduction of IFLF OTA-C filter, a fifth-order IFLFOTA-C filter is designed. Because of the imprecise of components, these filters need tobe tuned. There are two kinds of tuning method, dirtect tuning and indirtect tuning. Inthis thesis, the peak detection tuning is studied. The Simulation result shows that IFLFOTA-C filter meets the requirements of the design.更多还原