多模发射机中的可变增益模拟低通滤波器设计

【作者】 余永长；

【导师】 闵昊；

【作者基本信息】 复旦大学 ， 微电子学与固体电子学， 2011， 硕士

【摘要】 无线通信技术和CMOS工艺的迅速发展使得单片集成多模通信系统成为可能。在多标准无线收发系统设计中最大化硬件重用率可以降低芯片制造成本,这成为当今重要的研究课题之一,因此,可配置是无线通信系统中模拟基带电路设计的关键。另外,便携式通信终端还要求功耗低,片外元器件少。本文研究了多模发射机中模拟基带滤波器的电路理论和实现方法,针对关键性能指标提出优化方案。首先,本文从GSM, TD-SCDMA和WCDMA多模发射机系统架构的角度分析了系统的性能要求。接着,分析了模拟滤波器的基本类型和各自的优缺点,并阐述模拟滤波器的设计流程,并分析了Tow-Thomas两种双二阶单元(Biquad)在线性度方面的差异。随后,本文设计了一款应用于GSM, TD-SCDMA和WCDMA多模发射机中,具备增益及带宽可调和自动频率校准功能的四阶切比雪夫Active-RC型低通模拟滤波器。并就滤波器的噪声和线性度提出优化方法。最后,介绍了芯片版图设计考虑,通过一次流片测试验证了电路的基本理论和设计方法的正确性,并就关注的性能进一步提出优化思路。测试结果显示芯片各项指标基本满足多模发射机的系统要求。更多还原

【Abstract】 With the development of wireless communication and CMOS technology, it becomes realistic to integrate different communication protocols on single chip. Realizing multi-standard transceivers with maximum hardware reuse is of great importance to minimize the manufacturing cost. Therefore, reconfigurability is a key point in the design of the analog baseband circuits. In addition, the reduction of power consumption and off-chip components is also a key design issue in enhancing portability and battery operation. This work focuses on the circuit theory and implementation method of baseband filter in multi-mode transmitters. Circuit optimization methods are presented in this thesis to improve some key performances of baseband filter.Firstly, this work analyses the performance requirements of GSM, TD-SCDMA and WCDMA multi-mode transmitters.Secondly, different types of analog filters are compared and the design flow of analog filters is presented. The linearity performance of Tow-Thomas biquad is analysed.Further, this paper describes a low-pass reconfigurable baseband filter for GSM, TD-SCDMA and WCDMA multi-mode transmitters. The baseband filter incorporates -40 to 0 dB programmable gain control. An automatic frequency tuning (AFT) circuit is adopted to compensate the cut-off frequency variation. The filter’s cut-off frequency can be reconfigured for GSM/TD-SCDMA/WCDMA multi-mode transmitter. The out-of-band noise performance and in-band linearity performance are optimized.Finally, the layout considerations are presented. The basic circuit theory and design method are verified. An optimization design is put forward to improve the filter’s concerned performance. Measurement results show that the design meets demands of the system.更多还原