Rf Receiver Automatic Gain Control Circuit Design

Digital Television(DTV) is evitably replacing the traditional analog TV in recent years.The digital TV tuner,especially in the CMOS single-chip solution,takes an important role in the DTV industry.Auto Gain Control(AGC) is implemented in tuner to provide constant signal power to quantizing and demodulating models for unpredictable received signal strengths from antenna.The performance of AGC is of significant importance to the whole wireless receiver.AGC with wide dynamic range improves the dynamic range of tuner.And AGC with low power help reduce the total power consumption of tuner.Moreover,AGC with short set-up time enable the tuner to switch between channels or adjust to variable environment quickly.This work presents the analysis and design of the AGC part in single-chip tuner. The architecture and specification is analyzed and main blocks are designed as well as taped out and tested.Firstly,an overview about the basic function and specification of the AGC part is presented.Secondly,the gain,noise and linearity requirements of IF amplifiers are analyzed and calculated based on the DVB-T standard.Further,the programmable gain amplifiers(PGA),DC offset cancellation circuits(DCOC) and received signal strength indicator(RSSI) were designed, taped out and tested.Analyze of measurement results shows that the requirements of the tuner is satisfied.