数字电视接收系统中射频前端电路研究与设计 Abstract As an important component of receiver,RF Front-end generally consists of two modules:low noise amplifier and down conversion mixer.The standards of digital TV give many performance requirements for digital TV receiver.Those requirements will reflect themselves in the course of designing RF Front-end circuit.This paper will focus on the analysis and design of two modules of RF Front-end in the application background of digital TV receiver system. Firstly,this paper classifies the general system specs of RF Front-end into three categories:specs about noise,specs about nonlinearity and others specs,the fundamental principle of these specs and their relationships will be elaborated in detail.The specs of cascade system and the choice of receiver architectures also will be described. Secondly,this paper systematically discusses problems about low noise amplifier such as noise optimization,linearity optimization,and input matching optimization at different gain.Furthermore,a wideband variable gain low noise amplifier suitable for multi-standard digital TV receiver system is designed. Thirdly,after the analysis of current drive passive mixer's performances such as gain,input impedance,noise and nonlinearity is finished,a variable gain current drive passive mixer is designed.It is also suitable for multi-standard digital TV receiver system. Lastly,the digital TV receiver chip including the RF Front-end designed in this paper is taped out in TSMC 0.18 um CMOS process.The measurement results show that the minimum NF is 2.0 dB among the frequency range of 50 ~250 MHz and 470~862 MHz and the maximum NF is 3.5 dB;the gain range of low noise amplifier is from-22 ~20 dB with 2 dB/step and the mixer is from 9 ~31 dB with 1.5 dB/step;the //P3 at maximum LNA gain mode is-8 dBm and is 27 dBm at minimum LNA gain mode;S11 is smaller than-9.7 dB at different gain among the whole frequency range Keywords:Receiver,RF Front-end,Low Noise Amplifier,Mixer,Noise, Linearity,Digital TV Classification Code:TN432数字电视接收系统中射频前端电路研究与设计 2 Abstract As an important component of receiver, RF Front-end generally consists of two modules: low noise amplifier and down conversion mixer. The standards of digital TV give many performance requirements for digital TV receiver. Those requirements will reflect themselves in the course of designing RF Front-end circuit. This paper will focus on the analysis and design of two modules of RF Front-end in the application background of digital TV receiver system. Firstly, this paper classifies the general system specs of RF Front-end into three categories: specs about noise, specs about nonlinearity and others specs, the fundamental principle of these specs and their relationships will be elaborated in detail. The specs of cascade system and the choice of receiver architectures also will be described. Secondly, this paper systematically discusses problems about low noise amplifier such as noise optimization, linearity optimization, and input matching optimization at different gain. Furthermore, a wideband variable gain low noise amplifier suitable for multi-standard digital TV receiver system is designed. Thirdly, after the analysis of current drive passive mixer’s performances such as gain, input impedance, noise and nonlinearity is finished, a variable gain current drive passive mixer is designed. It is also suitable for multi-standard digital TV receiver system. Lastly, the digital TV receiver chip including the RF Front-end designed in this paper is taped out in TSMC 0.18 µm CMOS process. The measurement results show that the minimum NF is 2.0 dB among the frequency range of 50 ~ 250 MHz and 470 ~ 862 MHz and the maximum NF is 3.5 dB; the gain range of low noise amplifier is from -22 ~ 20 dB with 2 dB/step and the mixer is from 9 ~ 31 dB with 1.5 dB/step; the IIP3 at maximum LNA gain mode is -8 dBm and is 27 dBm at minimum LNA gain mode; S11 is smaller than -9.7 dB at different gain among the whole frequency range. Keywords: Receiver, RF Front-end, Low Noise Amplifier, Mixer, Noise, Linearity, Digital TV Classification Code: TN432