According to the theories of optimal noise match and optimal power match, a method for calculating the optimal source impedance of low noise amplifier （LNA） is proposed based on the input reflection coefficient S11....According to the theories of optimal noise match and optimal power match, a method for calculating the optimal source impedance of low noise amplifier （LNA） is proposed based on the input reflection coefficient S11. Moreover.with the help of Smith chart, the calculation process is detailed, and the trade-off between the lowest noise figure and the maximum power gain is obtained during the design of LNA input impedance matching network. Based on the Chart 0. 35-μm CMOS process, a traditional cascode LNA circuit is designed and manufactured. Simulation and experimental results have a good agreement with the theoretical analysis, thus proving the correctness of theoretical analysis and the feasibility of the method.展开更多
The reconstruction of background noise from an error signal of an adaptive filter is a key issue for developing Variable Step-Size Normalized Least Mean Square (VSS-NLMS) algorithm in the context of Echo Cancellation ...The reconstruction of background noise from an error signal of an adaptive filter is a key issue for developing Variable Step-Size Normalized Least Mean Square (VSS-NLMS) algorithm in the context of Echo Cancellation (EC). The core parameter in this algorithm is the Background Noise Power (BNP); in the estimation of BNP, the power difference between the desired signal and the filter output, statistically equaling to the error signal power, has been widely used in a rough manner. In this study, a precise BNP estimate is implemented by multiplying the rough estimate with a corrective factor, taking into consideration the fact that the error signal consists of background noise and misalignment noise. This corrective factor is obtained by subtracting half of the latest VSS value from 1 after analyzing the ratio of BNP to the misalignment noise. Based on the precise BNP estimate, the PVSS-NLMS algorithm suitable for the EC system is eventually proposed. In practice, the proposed algorithm exhibits a significant advantage of easier controllability application, as prior knowledge of the EC environment can be neglected. The simulation results support the preciseness of the BNP estimation and the effectiveness of the proposed algorithm.展开更多
The full-duplex(FD) based wireless communication devices,which are capable of concurrently transmitting and receiving signals with a single frequency band,suffer from a severe self-interference(SI) due to the large po...The full-duplex(FD) based wireless communication devices,which are capable of concurrently transmitting and receiving signals with a single frequency band,suffer from a severe self-interference(SI) due to the large power difference between the devices' own transmission and the useful signal comes from the remote transmitters. To enable the practical FD devices to be implementable,the SI power must be sufficiently suppressed to the level of background noise power,making the received signal-to-interference-plus-noise ratio(SINR) satisfy the decoding requirement. In this paper,the design and implementation of the duplexer for facilitating SI cancellation in FD based wireless communications are investigated,with a new type of duplexer(i.e. an improved directional coupler) designed for improving the spatial suppression of the SI power. Furthermore,the practical circuit boards are designed and verified for the proposed prototype,showing that the spatial suppression capability may be up to 36 d B(i.e. much higher than that attainable in the commonly designed ferrite circulator) by using the proposed design.展开更多
基金Supported by the Nature Science Foundation for Key Program of Jiangsu Higher Education Institu-tions of China(09KJA510001)the Creative Talents Foundation of Nantong Universitythe Scientific ResearchFoundation of Nantong University(08B24,09ZW005)~~
文摘According to the theories of optimal noise match and optimal power match, a method for calculating the optimal source impedance of low noise amplifier （LNA） is proposed based on the input reflection coefficient S11. Moreover.with the help of Smith chart, the calculation process is detailed, and the trade-off between the lowest noise figure and the maximum power gain is obtained during the design of LNA input impedance matching network. Based on the Chart 0. 35-μm CMOS process, a traditional cascode LNA circuit is designed and manufactured. Simulation and experimental results have a good agreement with the theoretical analysis, thus proving the correctness of theoretical analysis and the feasibility of the method.
文摘The reconstruction of background noise from an error signal of an adaptive filter is a key issue for developing Variable Step-Size Normalized Least Mean Square (VSS-NLMS) algorithm in the context of Echo Cancellation (EC). The core parameter in this algorithm is the Background Noise Power (BNP); in the estimation of BNP, the power difference between the desired signal and the filter output, statistically equaling to the error signal power, has been widely used in a rough manner. In this study, a precise BNP estimate is implemented by multiplying the rough estimate with a corrective factor, taking into consideration the fact that the error signal consists of background noise and misalignment noise. This corrective factor is obtained by subtracting half of the latest VSS value from 1 after analyzing the ratio of BNP to the misalignment noise. Based on the precise BNP estimate, the PVSS-NLMS algorithm suitable for the EC system is eventually proposed. In practice, the proposed algorithm exhibits a significant advantage of easier controllability application, as prior knowledge of the EC environment can be neglected. The simulation results support the preciseness of the BNP estimation and the effectiveness of the proposed algorithm.
基金supported by the key project of the National Natural Science Foundation of China(No.61431001)the 5G research program of China Mobile Research Institute (No.[2015] 0615)+1 种基金Key Laboratory of Cognitive Radio and Information Processing,Ministry of Education(Guilin University of Electronic Technology)the Foundation of Beijing Engineering and Technology Center for Convergence Networks and Ubiquitous Services
文摘The full-duplex(FD) based wireless communication devices,which are capable of concurrently transmitting and receiving signals with a single frequency band,suffer from a severe self-interference(SI) due to the large power difference between the devices' own transmission and the useful signal comes from the remote transmitters. To enable the practical FD devices to be implementable,the SI power must be sufficiently suppressed to the level of background noise power,making the received signal-to-interference-plus-noise ratio(SINR) satisfy the decoding requirement. In this paper,the design and implementation of the duplexer for facilitating SI cancellation in FD based wireless communications are investigated,with a new type of duplexer(i.e. an improved directional coupler) designed for improving the spatial suppression of the SI power. Furthermore,the practical circuit boards are designed and verified for the proposed prototype,showing that the spatial suppression capability may be up to 36 d B(i.e. much higher than that attainable in the commonly designed ferrite circulator) by using the proposed design.
