Man made electromagnetic irradiation and fields cover now the globe due to the recent extensive propagation of mobile telephony.The increased load affects animals and also plants.Especially birds have been studied.Hum...Man made electromagnetic irradiation and fields cover now the globe due to the recent extensive propagation of mobile telephony.The increased load affects animals and also plants.Especially birds have been studied.Humans are also sensitive.They are good bioindicators as epidemiological methods are available.Humans can also report symptoms which cannot be directly measured with presently available technologies.The nonionizing irradiation can as the ionizing one break the DNA,damage proteins,even increase the blood brain barrier permeability,disturb the night rest,cause fatigue and hormonal disturbances.An increase of the tumours of human head has been described in correlation with the long term mobile phone use and on that side more exposed.The regulations covering mobile telephony are already about two decades old and need re-evaluation.The multitude of irradiation and the interaction of the different wavelength exposures,i.e.,frequency sensitivity is poorly known at present.We should not forget the comparative studies of different species especially those which rely in their lives on electromagnetic orientation physiology.Some countries have issued warnings on the exposures of children.The producers of mobile technology have recently warned the users not to keep those devices in active stage in skin contact.展开更多
In modern wireless communication systems,the signal-to-noise ratio(SNR)is one of the most important performance indicators.When the other radio frequency(RF)performance of the components is well designed,passive inter...In modern wireless communication systems,the signal-to-noise ratio(SNR)is one of the most important performance indicators.When the other radio frequency(RF)performance of the components is well designed,passive intermodulation(PIM)interference may become an important factor limiting the system’s SNR.Whether it is a base station,an indoor distributed antenna system,or a satellite system,there are stringent PIM level requirements to minimize interference and enhance network capacity in multicarrier networks.Especially for systems of high power and wide bandwidth such as 5G wireless communication,PIM interference is even more serious.Due to the complexity and uncertainty of PIM,measurement is the most important means to study and evaluate the PIM performance of wireless communication systems.In this review,the current main PIM measurement methods recommended by International Electrotechnical Commission(IEC)and other standard organizations are introduced,and several key challenges in PIM measurement and their solutions(including the design of PIM tester,the location of the PIM sources,the design of compact PIM anechoic chambers,and the evaluation methods of PIM anechoic chambers)are highlighted.These challenges are of great significance to solve PIM problems that may arise during device characterization and verification in real wireless communication systems.展开更多
This paper describes the job carried out for the developing of an analytical model that is able to calculates the input impedance of a power distribution network(PDN)by taking into account modeling of package and PCB....This paper describes the job carried out for the developing of an analytical model that is able to calculates the input impedance of a power distribution network(PDN)by taking into account modeling of package and PCB.PDNs are usually already widely available,the work focuses on the chip and interposer PDN.The model has been used by an optimizer to determine the optimum position of the decoupling capacitors to be connected to the PDN.展开更多
Aiming to the estimation of source numbers, mixing matrix and separation of mixing signals under underdetermined case, the article puts forward a method of underdetermined blind source separation （UBSS） with an appl...Aiming to the estimation of source numbers, mixing matrix and separation of mixing signals under underdetermined case, the article puts forward a method of underdetermined blind source separation （UBSS） with an application in ultra-wideband （UWB） communication signals. The method is based on the sparse characteristic of UWB communication signals in the time domain. Firstly, finding the single source area by calculating the ratio of observed sampling points. Then an algorithm called hough-windowed method was introduced to estimate the number of sources and mixing matrix. Finally the separation of mixing signals using a method based on amended subspace projection. The simulation results indicate that the proposed method can separate UWB communication signals successfully, estimate the mixing matrix with higher accuracy and separate the mixing signals with higher gain compared with other conventional algorithms. At the same time, the method reflects the higher stability and the better noise immunity.展开更多
文摘Man made electromagnetic irradiation and fields cover now the globe due to the recent extensive propagation of mobile telephony.The increased load affects animals and also plants.Especially birds have been studied.Humans are also sensitive.They are good bioindicators as epidemiological methods are available.Humans can also report symptoms which cannot be directly measured with presently available technologies.The nonionizing irradiation can as the ionizing one break the DNA,damage proteins,even increase the blood brain barrier permeability,disturb the night rest,cause fatigue and hormonal disturbances.An increase of the tumours of human head has been described in correlation with the long term mobile phone use and on that side more exposed.The regulations covering mobile telephony are already about two decades old and need re-evaluation.The multitude of irradiation and the interaction of the different wavelength exposures,i.e.,frequency sensitivity is poorly known at present.We should not forget the comparative studies of different species especially those which rely in their lives on electromagnetic orientation physiology.Some countries have issued warnings on the exposures of children.The producers of mobile technology have recently warned the users not to keep those devices in active stage in skin contact.
文摘In modern wireless communication systems,the signal-to-noise ratio(SNR)is one of the most important performance indicators.When the other radio frequency(RF)performance of the components is well designed,passive intermodulation(PIM)interference may become an important factor limiting the system’s SNR.Whether it is a base station,an indoor distributed antenna system,or a satellite system,there are stringent PIM level requirements to minimize interference and enhance network capacity in multicarrier networks.Especially for systems of high power and wide bandwidth such as 5G wireless communication,PIM interference is even more serious.Due to the complexity and uncertainty of PIM,measurement is the most important means to study and evaluate the PIM performance of wireless communication systems.In this review,the current main PIM measurement methods recommended by International Electrotechnical Commission(IEC)and other standard organizations are introduced,and several key challenges in PIM measurement and their solutions(including the design of PIM tester,the location of the PIM sources,the design of compact PIM anechoic chambers,and the evaluation methods of PIM anechoic chambers)are highlighted.These challenges are of great significance to solve PIM problems that may arise during device characterization and verification in real wireless communication systems.
文摘This paper describes the job carried out for the developing of an analytical model that is able to calculates the input impedance of a power distribution network(PDN)by taking into account modeling of package and PCB.PDNs are usually already widely available,the work focuses on the chip and interposer PDN.The model has been used by an optimizer to determine the optimum position of the decoupling capacitors to be connected to the PDN.
基金supported by the National Natural Science Foundation of China (61172038, 60831001)
文摘Aiming to the estimation of source numbers, mixing matrix and separation of mixing signals under underdetermined case, the article puts forward a method of underdetermined blind source separation （UBSS） with an application in ultra-wideband （UWB） communication signals. The method is based on the sparse characteristic of UWB communication signals in the time domain. Firstly, finding the single source area by calculating the ratio of observed sampling points. Then an algorithm called hough-windowed method was introduced to estimate the number of sources and mixing matrix. Finally the separation of mixing signals using a method based on amended subspace projection. The simulation results indicate that the proposed method can separate UWB communication signals successfully, estimate the mixing matrix with higher accuracy and separate the mixing signals with higher gain compared with other conventional algorithms. At the same time, the method reflects the higher stability and the better noise immunity.
