Discrete-time charge analysis for a digital RF charge sampling mixer  

作　　者：Yun PAN Ning GE Xiao-lang YAN Xiao-peng YU 

机构地区：[1]Institute of VLS1 Design, Zhejiang University, Hangzhou 310027, China [2]Department of Electronic Engineering, Tsinghua University, Beijing 100084, China

出　　处：《Journal of Zhejiang University-Science C(Computers and Electronics)》2010年第4期307-314,共8页浙江大学学报C辑（计算机与电子（英文版）

基　　金：supported by the National Natural Science Foundation of China (No.90407011);the National High-Tech Research and Development Program (863) of China (No.2007AA01Z2b3);China Postdoctoral Science Foundation (No.20090451439)

摘　　要：This paper presents an approach for analyzing the key parts of a general digital radio frequency(RF) charge sampling mixer based on discrete-time charge values.The cascade sampling and filtering stages are analyzed and expressed in theoretical formulae.The effects of a pseudo-differential structure and CMOS switch-on resistances on the transfer function are addressed in detail.The DC-gain is restrained by using the pseudo-differential structure.The transfer gain is reduced because of the charge-sharing time constant when taking CMOS switch-on resistances into account.The unfolded transfer gains of a typical digital RF charge sampling mixer are analyzed in different cases using this approach.A circuit-level model of the typical mixer is then constructed and simulated in Cadence SpectreRF to verify the results.This work informs the design of charge-sampling,infinite impulse response(ⅡR) filtering,and finite impulse response(FIR) filtering circuits.The discrete-time approach can also be applied to other multi-rate receiver systems based on charge sampling techniques.This paper presents an approach for analyzing the key parts of a general digital radio frequency （RF） charge sampling mixer based on discrete-time charge values. The cascade sampling and filtering stages are analyzed and expressed in theoretical formulae. The effects of a pseudo-differential structure and CMOS switch-on resistances on the transfer function are addressed in detail. The DC-gain is restrained by using the pseudo-differential structure. The transfer gain is reduced because of the charge-sharing time constant when taking CMOS switch-on resistances into account. The unfolded transfer gains of a typical digital RF charge sampling mixer are analyzed in different cases using this approach. A circuit-level model of the typical mixer is then constructed and simulated in Cadence SpectreRF to verify the results. This work informs the design of charge-sampling, infinite impulse response （IIR） filtering, and finite impulse response （FIR） filtering circuits. The discrete-time approach can also be applied to other multi-rate receiver systems based on charge sampling techniques.

关 键 词：Digital RF Charge sampling DISCRETE-TIME Pseudo-differential Switch-on resistance 

分 类 号：TN710[电子电信—电路与系统]