The error vector magnitude（EVM） is extensively applied as a metric for digital transmitter signal quality compliance in modern communication systems.This article is focused on the effects of local oscillator（LO） p...The error vector magnitude（EVM） is extensively applied as a metric for digital transmitter signal quality compliance in modern communication systems.This article is focused on the effects of local oscillator（LO） phase noise and nonlinear distortion of power amplifier on EVM.This article contributes to below aspects.First,the relationships between EVM and two effects,LO phase noise and nonlinear distortion of power amplifier,are derived and expressed.Second,to simplify the expression,the third-order intermodulation distortion（IMD3） is used to calculate the EVM.Then,an expression for the EVM is derived based on the digital transmitter model that considers local oscillator phase noise and nonlinear distortion of power amplifier.Finally,the math formula of bit error rate（BER） versus EVM is given which can be easier and more useful to predict BER,according to analysis of the relationship between EVM and signal to noise rate（SNR）,inspired by the works of Rishad,Md.Shahriar and AHM,2006.Simulations are carried out to display the performance of EVM based on these relationships.展开更多
he influence of laser linewidth on optical fiber transmission systems has been investigated. The maximum transmission distances at different linewidths are first calculated in linear systems with various bit rates. Th...he influence of laser linewidth on optical fiber transmission systems has been investigated. The maximum transmission distances at different linewidths are first calculated in linear systems with various bit rates. Then it is found that SPM can significantly enhance the PMAM noise which severely deteriorates the performance of system with high optical power and large dispersion. In this case, the laser linewidth and optical power must be well controlled.展开更多
The technique of SNR estimation is one of the key technologies in adaptive frequency hopping system. The methods of channel quality estimation for non-linear continuous phase modulation (CPM) signals have some limitat...The technique of SNR estimation is one of the key technologies in adaptive frequency hopping system. The methods of channel quality estimation for non-linear continuous phase modulation (CPM) signals have some limitations. Therefore, the algorithm of channel quality estimation for CPM signals is worthy of further study. Some similar phase characteristics between sampling CPM and MPSK motivate us to propose a channel estimation algorithm with applications to nonlinear CPM using linear modulation signal processing. A comprehensive analysis of LDPC-CPM schemes using proposed algorithm is presented, and simulation results indicate that the proposed method can not only estimate channel quality well but also make the normalized MSE (NMSE) of SNR estimate close to/less than 0.1 dB at SNR of 4 dB using short block codes. It shows that the algorithm in this paper is effective enough to estimate the signal to noise ratio (SNR). Meanwhile, the algorithm in this paper reduces the complexity of computation compared with other traditional algorithms.展开更多
基金supported by the National Natural Science Foundation Project of CQ CSTC of China (2008BB2168)
文摘The error vector magnitude（EVM） is extensively applied as a metric for digital transmitter signal quality compliance in modern communication systems.This article is focused on the effects of local oscillator（LO） phase noise and nonlinear distortion of power amplifier on EVM.This article contributes to below aspects.First,the relationships between EVM and two effects,LO phase noise and nonlinear distortion of power amplifier,are derived and expressed.Second,to simplify the expression,the third-order intermodulation distortion（IMD3） is used to calculate the EVM.Then,an expression for the EVM is derived based on the digital transmitter model that considers local oscillator phase noise and nonlinear distortion of power amplifier.Finally,the math formula of bit error rate（BER） versus EVM is given which can be easier and more useful to predict BER,according to analysis of the relationship between EVM and signal to noise rate（SNR）,inspired by the works of Rishad,Md.Shahriar and AHM,2006.Simulations are carried out to display the performance of EVM based on these relationships.
文摘he influence of laser linewidth on optical fiber transmission systems has been investigated. The maximum transmission distances at different linewidths are first calculated in linear systems with various bit rates. Then it is found that SPM can significantly enhance the PMAM noise which severely deteriorates the performance of system with high optical power and large dispersion. In this case, the laser linewidth and optical power must be well controlled.
文摘The technique of SNR estimation is one of the key technologies in adaptive frequency hopping system. The methods of channel quality estimation for non-linear continuous phase modulation (CPM) signals have some limitations. Therefore, the algorithm of channel quality estimation for CPM signals is worthy of further study. Some similar phase characteristics between sampling CPM and MPSK motivate us to propose a channel estimation algorithm with applications to nonlinear CPM using linear modulation signal processing. A comprehensive analysis of LDPC-CPM schemes using proposed algorithm is presented, and simulation results indicate that the proposed method can not only estimate channel quality well but also make the normalized MSE (NMSE) of SNR estimate close to/less than 0.1 dB at SNR of 4 dB using short block codes. It shows that the algorithm in this paper is effective enough to estimate the signal to noise ratio (SNR). Meanwhile, the algorithm in this paper reduces the complexity of computation compared with other traditional algorithms.
