Research And Design Of High Linearity Gm-C Complex Filter

In recent years,the rapid development of wireless communication technology and semiconductor technology has caused various miniaturized and low-cost wireless communication devices to slowly integrate into our lives.In the wireless communication network,the radio frequency transceiver as the key module of the system to receive and transmit information,determines the performance of the wireless communication system.The complex filter is a key module of the RF transceiver system.Improving the performance of the complex filter is of great significance to improving the performance of the RF system.Based on the basic theoretical study of traditional real filter circuit,the thesis studies and learns the basic concepts of complex filter and important performance indicators.In view of the low linearity of Gm-C filters and the increasing requirements of modern wireless transceivers for low power consumption,low cost and high integration,two high-linearity Gm-designed for low-IF receivers C complex filter.The main work and innovations are as follows:(1)The transconductance amplifier is the core module of the Gm-C complex filter,and its linearity affects the performance of the entire complex filter.In view of the shortcomings of the low linearity of the open loop operation of the traditional transconductance op amp,this paper proposes a highly linear transconductance amplifier,which uses linearization techniques such as source negative feedback resistance,cross coupling and adaptive bias to expand the Input range,reduce third-order distortion to improve linearity.Based on the transconductance amplifier,a cascaded biquad high linear Gm-C complex filter is designed.The design is based on the UMC 110 nm CMOS process.Cadence simulation results show that at a 1.2V supply voltage,its center frequency is 4MHz,bandwidth is 2MHz,linearity is 12.64 dBm,image rejection ratio is 31 dB,and power consumption is 1300?W.The results show that the complex filter under study has good linearity performance.(2)Aiming at the problem of insufficient linearity of the low power supply voltage Gm-C complex filter,a first-order complex band-pass filter using large-signal linearization technique is proposed.The proposed complex filter uses two linearization techniques,unbalanced differential pair technology and adaptive bias circuit,to increase the linearity of the filter by extending the input voltage range of the transconductance.At the same time,the current multiplexing structure is applied to the complex filter,which greatly reduces the power consumption of the filter.The design uses UMC 110 nm CMOS process,Cadence simulation results show that at 1.2V power supply voltage,its center frequency is 2MHz,bandwidth is 1MHz,linearity is 9.5dB,image rejection ratio is 18 dB,power consumption is 229?W.The complex filter studied has the characteristics of simple structure,high linearity and low power consumption.