A nonlinear single neuron is demonstrated to exhibit stochastic resonance by theoretical analysis and numerical simulations. This single neuron is used for noisy periodic signal transmission, and significant performan...A nonlinear single neuron is demonstrated to exhibit stochastic resonance by theoretical analysis and numerical simulations. This single neuron is used for noisy periodic signal transmission, and significant performance of raising input output SNR gain can be achieved. The research of this paper not only gives a very simple model of neuron with stochastic resonance, but also enlarges the application scope of neuron to the transmission of periodic signals.展开更多
Based on our previous work, we study the problem of neural signal transmission of myelinated neurons. We found that the transmembrane ion current at Ranvier's node acts as an energy supplement. In addition, the le...Based on our previous work, we study the problem of neural signal transmission of myelinated neurons. We found that the transmembrane ion current at Ranvier's node acts as an energy supplement. In addition, the length of the myelin sheath has an upper limit of lT. Above this upper limit, the neural signal will not be effectively transmitted. In the range of normal physiological parameters, lT is on the order of mm. Finally, the effect of temperature on the transmission of nerve signals is investigated. temperatures that are too high and too low are not conducive to the conduction of nerve signals.展开更多
Statistical Signal Transmission(SST)is a technique based on orthogonal frequency-division multiplexing(OFDM)and adopts cyclostationary features,which can transmit extra information without additional bandwidth.However...Statistical Signal Transmission(SST)is a technique based on orthogonal frequency-division multiplexing(OFDM)and adopts cyclostationary features,which can transmit extra information without additional bandwidth.However,the more complicated environment in 5G communication systems,especially the fast time-varying scenarios,will dramatically degrade the performance of the SST.In this paper,we propose a fragmental weight-conservation combining(FWCC)scheme for SST,to overcome its performance degradation under fast time-varying channels.The proposed FWCC scheme consists of three phases:1、incise the received OFDM stream into pieces;2、endue different weights for fine and contaminated pieces,respectively;3、combine cyclic autocorrelation function energies of all the pieces;and 4、compute the final feature and demodulate data of SST.Through these procedures above,the detection accuracy of SST will be theoretically refined under fast time-varying channels.Such an inference is confirmed through numerical results in this paper.It is demonstrated that the BER performance of proposed scheme outperforms that of the original scheme both in ideal channel estimation conditions and in imperfect channel estimation conditions.In addition,we also find the experiential optimal weight distribution strategy for the proposed FWCC scheme,which facilitates practical applications.展开更多
Based on the electromagnetic field theory, the optical signal transmission characteristics in input/output waveguides, slab waveguides and arrayed waveguides of the arrayed waveguide grating (AWG) multi/demultiplexer ...Based on the electromagnetic field theory, the optical signal transmission characteristics in input/output waveguides, slab waveguides and arrayed waveguides of the arrayed waveguide grating (AWG) multi/demultiplexer are analyzed. The relationship between the physical parameters such as geometry sizes and relative refractive index in AWG multi/demultiplexer and the optical signal transmission characteristics are discussed. This theoretical study can be used for optimizing the design and improving the performance of the AWG multi/demultiplexer.展开更多
The aim of this work was to investigate the electrical resistance change of electro-textiles manufactured using cotton fabrics with stainless steel and silver plated PA yarns incorporation after being subjected to hom...The aim of this work was to investigate the electrical resistance change of electro-textiles manufactured using cotton fabrics with stainless steel and silver plated PA yarns incorporation after being subjected to home laundering, i.e. detergent washing and silicone softening. Electrical resistances of conductive yams inside the fabric structure were compared and discussed statistically before and after washing and softener application. Greatest changes in electrical resistances were observed with samples including silver plated PA yams. After five washing cycles with detergent, silicone softening agent is removed from yarns by washing, and thus conductivity increases. Further washing of e-textiles with detergent for five more cycles causes decrease in conductivity, because of chemical effects of detergent and mechanical effects of washing process such as abrasion due to friction. Detergent which has negative reactive sites bonds with metal ions reduces conductivity.展开更多
A numerical model and transmission characteristic analysis of DPSK (differential phase shift keying) pressure signals in mud channels is introduced. With the control logic analysis of the rotary valve mud telemetry,...A numerical model and transmission characteristic analysis of DPSK (differential phase shift keying) pressure signals in mud channels is introduced. With the control logic analysis of the rotary valve mud telemetry, a logical control signal is built from a Gate function sequence according to the binary symbols of transmitted data and a phase-shift function is obtained by integrating the logical control signal. A mathematical model of the DPSK pressure signal is built based on principles of communications by modulating carrier phase with the phase-shift function and a numerical simulation of the pressure wave is implemented with the mathematical model by MATLAB programming. Considering drillpipe pressure and drilling fluid temperature profile along drillpipes, the drillpipe of a vertical well is divided into a number of sections. With water-based drilling fluids, the impacts of travel distance, carrier frequency, drillpipe size, and drilling fluids on the signal transmission were studied by signal transmission characteristic analysis for all the sections. Numerical calculation results indicate that the influences of the viscosity of drilling fluids and volume fraction of gas in drilling fluids on the DPSK signal transmission are more notable than the others and the signal will distort in waveform with differential attenuations of the signal frequent component.展开更多
We comprehensively characterize the transmission performance of m-ary quadrature amplitude modulation(m-QAM) signals through a silicon microring resonator in the experiment. Using orthogonal frequency-division multipl...We comprehensively characterize the transmission performance of m-ary quadrature amplitude modulation(m-QAM) signals through a silicon microring resonator in the experiment. Using orthogonal frequency-division multiplexing based on offset QAM(OFDM/OQAM) which is modulated with m-QAM modulations, we demonstrate low-penalty data transmission of OFDM/OQAM 64-QAM, 128-QAM, 256-QAM, and 512-QAM signals in a silicon microring resonator. The observed optical signal-to-noise ratio(OSNR) penalties are 1.7 dB for 64-QAM,1.7 dB for 128-QAM, and 3.1 dB for 256-QAM at a bit-error rate(BER) of 2 × 10^(-3) and 3.3 dB for 512-QAM at a BER of 2 × 10^(-2). The performance degradation due to the wavelength detuning from the microring resonance is evaluated, showing a wavelength range of ~0.48 nm with BER below 2 × 10^(-3). Moreover, we demonstrate data transmission of 191.2-Gbit/s simultaneous eight wavelength channel OFDM/OQAM 256-QAM signals in a silicon microring resonator, achieving OSNR penalties less than 2 dB at a BER of 2 × 10^(-2).展开更多
We propose and experimentally demonstrate a novel scheme to realize polarization-division-multiplexing quadrature-phase-shift-keying (PDM-QPSK) signal transmission over fiber, wireless and fiber at Wband (75-110 GH...We propose and experimentally demonstrate a novel scheme to realize polarization-division-multiplexing quadrature-phase-shift-keying (PDM-QPSK) signal transmission over fiber, wireless and fiber at Wband (75-110 GHz). The generation of polarization multiplexing millimeter-wave (mm-wave) wireless signal is based on the photonic technique. After 20-km fiber transmission, polarization diversity and heterodyne beating are implemented to convert the polarization components of the polarization-multiplexing signals from the optical baseband to W-band so that up to 16 Gb/s mm-wave signals can be delivered over 2-m 2~2 multiple-input multiple-output (MIMO) wireless link. At the receiver base station (BS), polarization combination reconstructs the PDM-QPSK signal which is then launched into another 20-km fiber. In the experiment, coherent detection is introduced to improve receiver sensitivity and constant modulus algorithm (CMA) is applied for polarization de-multiplexing. The bit-error-ratio (BER) for 16-Gb/s PDM- QPSK signal delivery is below the forward-error-correction (FEC) threshold of 3.8× 10-3 with the optical signal-to-noise ratio (OSNR) above 11.8 dB.展开更多
Aimed at the rapid message setting of the passive systems, the efficiency of energy transmission and the characteristics of signal transmission in the message setting are analyzed, which is based on the methods of the...Aimed at the rapid message setting of the passive systems, the efficiency of energy transmission and the characteristics of signal transmission in the message setting are analyzed, which is based on the methods of the circuit analysis and the electromagnetic induction technology. A self-adaptive impedance matching method of signal and energy transmission, which can set the message rapidly and effectively, is put forward. The electromagnetic induct setting system will reach the highest energy transmission efficiency when the equivalent resistance of the second loop is equal to the resistance of the first loop. The greater the ratio of the equivalent resistances is, the higher efficient the signal transmission has. Moreover, the validity of the method is verified by circuit design and tests.展开更多
Due to the bandwidth limitation of the ultraviolet-C(UV-C) optical communication system and strong channel attenuation, it is difficult to transmit high-frequency signals. In this paper, the temporal ghost imaging(TGI...Due to the bandwidth limitation of the ultraviolet-C(UV-C) optical communication system and strong channel attenuation, it is difficult to transmit high-frequency signals. In this paper, the temporal ghost imaging(TGI) algorithm was first applied to the UV-C communication experimentally, and we realized the transmission of a 4 GHz signal through 95.34 MHz system bandwidth. The study indicates that the TGI algorithm can significantly improve the signal-to-noise ratio(SNR) compared with the on–off keying method. Our research provides a new approach for alleviating transmission frequency limitation due to poor SNR and insufficient hardware bandwidth.展开更多
We demonstrate the transmission of directly modulated 10-Gb/s WDM signals over 320 km of negative dispersion fiber (dispersion: -2.5 ps/km/nm @1550 nm) without dispersion compensation. The results indicate that a regi...We demonstrate the transmission of directly modulated 10-Gb/s WDM signals over 320 km of negative dispersion fiber (dispersion: -2.5 ps/km/nm @1550 nm) without dispersion compensation. The results indicate that a regional metro WDM network could be implemented cost-effectively by using the proposed negative dispersion fiber and direct modulated lasers.展开更多
The mRNA of insulin receptor (IR), the insulin receptor substrates (IRSs), glucose transporter 2 (GLUT2) and glucokinase (GK) in alloxan-induced diabetic rat livers were amplified by RT-PCR. The protein of the...The mRNA of insulin receptor (IR), the insulin receptor substrates (IRSs), glucose transporter 2 (GLUT2) and glucokinase (GK) in alloxan-induced diabetic rat livers were amplified by RT-PCR. The protein of the insulin receptor in rat livers was determined by westem-blotting. The results show that IR expression level decreased at the level of mRNA and protein. The gene expressions of IRSs, GLUT2 and GK changed significantly. The hepatic glycogen content in alloxan-diabetic rats treated with insulin ((13.2 ± 0.4) mg·g^-1) did not restore to normal level ((17.0 ±0.4) mg·g^-1) by means of anthrone-H2SO4 methods. The results imply that insulin resistance is developed during inchoate phase of alloxan-induced diabetic rats.展开更多
In this letter, we investigate quasi-cyclic low-density parity-check (QC-LDPC) codes in a 40-Gb/s nonreturn-to-zero differential phase-shift keying (NRZ-DPSK) signal transmission system based on a fiber- based opt...In this letter, we investigate quasi-cyclic low-density parity-check (QC-LDPC) codes in a 40-Gb/s nonreturn-to-zero differential phase-shift keying (NRZ-DPSK) signal transmission system based on a fiber- based optical parametric amplifier (FOPA). A constructed algorithm of QC-LDPC codes according to the optimizing set of shift vMues on the circulant permutation matrix (CPM) of the basis matrix is proposed. Simulation results prove that the coding gain in the encoded system can be realized at 10.2 dB under QC- LDPC codes with a code rate of 5/6 when the bit error rate (BER) is 10-9. In addition, the error-floor level originating from the uncoded system is suppressed.展开更多
The wireless communication system's performance is greatly constrained by the wireless channel characteristics,especially in some specific environment.Therefore,signal transmission will be greatly impacted even if...The wireless communication system's performance is greatly constrained by the wireless channel characteristics,especially in some specific environment.Therefore,signal transmission will be greatly impacted even if not in a complicated topography.Testing results show that it is hardly to characterize the radio propagation properties for the antenna installed on the ground.In order to ensure a successful communication,the radio frequency(RF)wireless signal intensity monitor system was designed.We can get the wireless link transmission loss through measuring signal strength from received node.The test shows that the near-ground wireless signal propagation characteristics still can be characterized by the log distance propagation loss model.These results will conduce to studying the transmission characteristic of Near-Earth wireless signals and will predict the coverage of the earth's surface wireless sensor network.展开更多
OAM (Operations, Administration and Maintenance) system is a very impo rtant component of 3G cellular network. In order to acquire overall managemen t, fast response and steady operation, an SCTP (Stream Control Trans...OAM (Operations, Administration and Maintenance) system is a very impo rtant component of 3G cellular network. In order to acquire overall managemen t, fast response and steady operation, an SCTP (Stream Control Transmission Prot ocol) based OAM, i.e., SOAM system was proposed. SOAM implements new characters of SCTP such as multi-stream, enforced SACK and heartbeat mechanism on its tran sport layer. These characters help SOAM decrease the message transmission delay and accelerate the link failure detection. Besides, a new component named SOAM agent was introduced to improve the operation efficiency of SOAM. The experim ental results prove the proposed SOAM system achieves better performance on sign aling transmission compared with conventional TCP based OAM system.展开更多
A new monostatic array system taking advantage of diverse waveforms to improve the performance of underwater tar- get localization is proposed. Unlike the coherent signals between different elements in common active a...A new monostatic array system taking advantage of diverse waveforms to improve the performance of underwater tar- get localization is proposed. Unlike the coherent signals between different elements in common active array, the transmitted signals from different elements here are spatially orthogonal waveforms which allow for array processing in the transit mode and result in an extension of array aperture. The mathematical derivation of Capon estimator for this sonar system is described in detail. And the performance of this orthogonal-waveform based sonar is an- alyzed and compared with that of its phased-array counterpart by water tank experiments. Experimental results show that this sonar system could achieve 12 dB-15 dB additional array gain over its phased-array counterpart, which means a doubling of maximum detection range. Moreover, the angular resolution is significantly improved at lower SNR.展开更多
This paper investigates the problem of real-time estimation for one kind of linear time invariant systems which subject to limited communication capacity. The communication limitations include signal transmission dela...This paper investigates the problem of real-time estimation for one kind of linear time invariant systems which subject to limited communication capacity. The communication limitations include signal transmission delay, the out-of-sequence measurements and data packet dropout, which appear typically in a network environment. The kernel of filter design is equally to formularize the traditional Kalman filter as one linear weighted summation which is composed of the initial state estimate and all sequential sampled measurements. For it can adapt aforementioned information limitations, the linear weighted summation is then decomposed into two stages. One is a predict-estimator composed by all reached measurements, another is one compensator constructed by those time-delayed data. In the network environment, there are obvious differences between the new hybrid filter and those existing delayed Kalman filters. For example, the novel filter can be optimal in the sense of linear minimum mean square error as soon as all measurements available and has the lowest running time than these existing delayed filters. One simulation, including two cases, is utilized to illustrate the design procedures proposed in this paper.展开更多
Ultra-densification of radio access network(RAN)is a key to efficiently support the exponentially growing mobile data traffic in 5 G era.Furthermore,extremely high frequency band like mm Wave band was utilized to solv...Ultra-densification of radio access network(RAN)is a key to efficiently support the exponentially growing mobile data traffic in 5 G era.Furthermore,extremely high frequency band like mm Wave band was utilized to solve the bandwidth shortage problem.However,untra-dense reusing the same radio resource produced severe interference.And the mm Wave link was very harsh due to frequent blockage by obstacles.Therefore a new RAN architecture needed to be introduced to realize ultra-reliable communications in such a severe radio propagation environment.An architecture of distributed MIMO based RAN was presented.Then,enhanced interference coordination(e IC)was described.Finally,the effectiveness of distributed MIMO based RAN with e IC by computer simulation was showed.展开更多
The problem of underdetermined blind source separation of adjacent satellite interference is proposed in this paper. Density Clustering algorithm(DC-algorithm) presented in this article is different from traditional m...The problem of underdetermined blind source separation of adjacent satellite interference is proposed in this paper. Density Clustering algorithm(DC-algorithm) presented in this article is different from traditional methods. Sparseness representation has been applied in underdetermined blind signal source separation. However, some difficulties have not been considered, such as the number of sources is unknown or the mixed matrix is ill-conditioned. In order to find out the number of the mixed signals, Short Time Fourier Transform(STFT) is employed to segment received mixtures. Then, we formulate the blind source signal as cluster problem. Furthermore, we construct Cost Function Pair and Decision Coordinate System by using density clustering. At the end of this paper, we discuss the performance of the proposed method and verify the novel method based on several simulations. We verify the proposed method on numerical experiments with real signal transmission, which demonstrates the validity of the proposed method.展开更多
Based on the former research results of the influence of contact failure in ideal and unmatched circuits, this paper further studies theoretically the effects of contact failure on the digital signal transmission in t...Based on the former research results of the influence of contact failure in ideal and unmatched circuits, this paper further studies theoretically the effects of contact failure on the digital signal transmission in the lossy circuits, which may happen widely in practical applications. Experiences show that even in high-quality lines, losses deform the voltage and current wave shapes owing to their effects on the amplitude of the various waves making up the over-all line voltage and current. Although the derivations show that the effects of contact failure in the lossy circuits on the signal transmission are quite complicated. The probability of occurrence of error codes can be increased significantly.展开更多
文摘A nonlinear single neuron is demonstrated to exhibit stochastic resonance by theoretical analysis and numerical simulations. This single neuron is used for noisy periodic signal transmission, and significant performance of raising input output SNR gain can be achieved. The research of this paper not only gives a very simple model of neuron with stochastic resonance, but also enlarges the application scope of neuron to the transmission of periodic signals.
基金Project supported in part by the National Defense Technology Innovation Special Zonethe National Natural Science Foundation of China(Grant Nos.51677145 and 11622542)。
文摘Based on our previous work, we study the problem of neural signal transmission of myelinated neurons. We found that the transmembrane ion current at Ranvier's node acts as an energy supplement. In addition, the length of the myelin sheath has an upper limit of lT. Above this upper limit, the neural signal will not be effectively transmitted. In the range of normal physiological parameters, lT is on the order of mm. Finally, the effect of temperature on the transmission of nerve signals is investigated. temperatures that are too high and too low are not conducive to the conduction of nerve signals.
基金supported by the National Natural Science Foundation of China (Nos. 61801461, 61801460)the Strategical Leadership Project of Chinese Academy of Sciences (grant No. XDC02070800)the Shanghai Municipality of Science and Technology Commission Project (Nos. 18XD1404100, 17QA1403800)
文摘Statistical Signal Transmission(SST)is a technique based on orthogonal frequency-division multiplexing(OFDM)and adopts cyclostationary features,which can transmit extra information without additional bandwidth.However,the more complicated environment in 5G communication systems,especially the fast time-varying scenarios,will dramatically degrade the performance of the SST.In this paper,we propose a fragmental weight-conservation combining(FWCC)scheme for SST,to overcome its performance degradation under fast time-varying channels.The proposed FWCC scheme consists of three phases:1、incise the received OFDM stream into pieces;2、endue different weights for fine and contaminated pieces,respectively;3、combine cyclic autocorrelation function energies of all the pieces;and 4、compute the final feature and demodulate data of SST.Through these procedures above,the detection accuracy of SST will be theoretically refined under fast time-varying channels.Such an inference is confirmed through numerical results in this paper.It is demonstrated that the BER performance of proposed scheme outperforms that of the original scheme both in ideal channel estimation conditions and in imperfect channel estimation conditions.In addition,we also find the experiential optimal weight distribution strategy for the proposed FWCC scheme,which facilitates practical applications.
文摘Based on the electromagnetic field theory, the optical signal transmission characteristics in input/output waveguides, slab waveguides and arrayed waveguides of the arrayed waveguide grating (AWG) multi/demultiplexer are analyzed. The relationship between the physical parameters such as geometry sizes and relative refractive index in AWG multi/demultiplexer and the optical signal transmission characteristics are discussed. This theoretical study can be used for optimizing the design and improving the performance of the AWG multi/demultiplexer.
文摘The aim of this work was to investigate the electrical resistance change of electro-textiles manufactured using cotton fabrics with stainless steel and silver plated PA yarns incorporation after being subjected to home laundering, i.e. detergent washing and silicone softening. Electrical resistances of conductive yams inside the fabric structure were compared and discussed statistically before and after washing and softener application. Greatest changes in electrical resistances were observed with samples including silver plated PA yams. After five washing cycles with detergent, silicone softening agent is removed from yarns by washing, and thus conductivity increases. Further washing of e-textiles with detergent for five more cycles causes decrease in conductivity, because of chemical effects of detergent and mechanical effects of washing process such as abrasion due to friction. Detergent which has negative reactive sites bonds with metal ions reduces conductivity.
基金supported by High Technology Research and Development Program of China(No.2006AA06A101).
文摘A numerical model and transmission characteristic analysis of DPSK (differential phase shift keying) pressure signals in mud channels is introduced. With the control logic analysis of the rotary valve mud telemetry, a logical control signal is built from a Gate function sequence according to the binary symbols of transmitted data and a phase-shift function is obtained by integrating the logical control signal. A mathematical model of the DPSK pressure signal is built based on principles of communications by modulating carrier phase with the phase-shift function and a numerical simulation of the pressure wave is implemented with the mathematical model by MATLAB programming. Considering drillpipe pressure and drilling fluid temperature profile along drillpipes, the drillpipe of a vertical well is divided into a number of sections. With water-based drilling fluids, the impacts of travel distance, carrier frequency, drillpipe size, and drilling fluids on the signal transmission were studied by signal transmission characteristic analysis for all the sections. Numerical calculation results indicate that the influences of the viscosity of drilling fluids and volume fraction of gas in drilling fluids on the DPSK signal transmission are more notable than the others and the signal will distort in waveform with differential attenuations of the signal frequent component.
基金National Program for Support of Top-Notch Young ProfessionalsNational Natural Science Foundation of China(NSFC)(11574001,11274131,61222502)Program for New Century Excellent Talents in University(NCET)(NCET-11-0182)
文摘We comprehensively characterize the transmission performance of m-ary quadrature amplitude modulation(m-QAM) signals through a silicon microring resonator in the experiment. Using orthogonal frequency-division multiplexing based on offset QAM(OFDM/OQAM) which is modulated with m-QAM modulations, we demonstrate low-penalty data transmission of OFDM/OQAM 64-QAM, 128-QAM, 256-QAM, and 512-QAM signals in a silicon microring resonator. The observed optical signal-to-noise ratio(OSNR) penalties are 1.7 dB for 64-QAM,1.7 dB for 128-QAM, and 3.1 dB for 256-QAM at a bit-error rate(BER) of 2 × 10^(-3) and 3.3 dB for 512-QAM at a BER of 2 × 10^(-2). The performance degradation due to the wavelength detuning from the microring resonance is evaluated, showing a wavelength range of ~0.48 nm with BER below 2 × 10^(-3). Moreover, we demonstrate data transmission of 191.2-Gbit/s simultaneous eight wavelength channel OFDM/OQAM 256-QAM signals in a silicon microring resonator, achieving OSNR penalties less than 2 dB at a BER of 2 × 10^(-2).
基金supported by the National Natural Science Foundation of China(Nos.61177071and 61250018)the National"863"Program of China(Nos.2011AA010302 and 2012AA011302)+1 种基金the National Key Technology R&D Program of China(No.2012BAH18B00)the International Cooperation Program of Shanghai Science and Technology Association(No.12510705600)
文摘We propose and experimentally demonstrate a novel scheme to realize polarization-division-multiplexing quadrature-phase-shift-keying (PDM-QPSK) signal transmission over fiber, wireless and fiber at Wband (75-110 GHz). The generation of polarization multiplexing millimeter-wave (mm-wave) wireless signal is based on the photonic technique. After 20-km fiber transmission, polarization diversity and heterodyne beating are implemented to convert the polarization components of the polarization-multiplexing signals from the optical baseband to W-band so that up to 16 Gb/s mm-wave signals can be delivered over 2-m 2~2 multiple-input multiple-output (MIMO) wireless link. At the receiver base station (BS), polarization combination reconstructs the PDM-QPSK signal which is then launched into another 20-km fiber. In the experiment, coherent detection is introduced to improve receiver sensitivity and constant modulus algorithm (CMA) is applied for polarization de-multiplexing. The bit-error-ratio (BER) for 16-Gb/s PDM- QPSK signal delivery is below the forward-error-correction (FEC) threshold of 3.8× 10-3 with the optical signal-to-noise ratio (OSNR) above 11.8 dB.
文摘Aimed at the rapid message setting of the passive systems, the efficiency of energy transmission and the characteristics of signal transmission in the message setting are analyzed, which is based on the methods of the circuit analysis and the electromagnetic induction technology. A self-adaptive impedance matching method of signal and energy transmission, which can set the message rapidly and effectively, is put forward. The electromagnetic induct setting system will reach the highest energy transmission efficiency when the equivalent resistance of the second loop is equal to the resistance of the first loop. The greater the ratio of the equivalent resistances is, the higher efficient the signal transmission has. Moreover, the validity of the method is verified by circuit design and tests.
基金This work was supported by the National Natural Science Foundation of China(NSFC)(Nos.61974031 and 61705041)Fudan University-CIOMP Joint Fund(No.FC2020-001)Shanghai Technical Standard Program(No.18DZ2206000).
文摘Due to the bandwidth limitation of the ultraviolet-C(UV-C) optical communication system and strong channel attenuation, it is difficult to transmit high-frequency signals. In this paper, the temporal ghost imaging(TGI) algorithm was first applied to the UV-C communication experimentally, and we realized the transmission of a 4 GHz signal through 95.34 MHz system bandwidth. The study indicates that the TGI algorithm can significantly improve the signal-to-noise ratio(SNR) compared with the on–off keying method. Our research provides a new approach for alleviating transmission frequency limitation due to poor SNR and insufficient hardware bandwidth.
文摘We demonstrate the transmission of directly modulated 10-Gb/s WDM signals over 320 km of negative dispersion fiber (dispersion: -2.5 ps/km/nm @1550 nm) without dispersion compensation. The results indicate that a regional metro WDM network could be implemented cost-effectively by using the proposed negative dispersion fiber and direct modulated lasers.
基金Supported by the National Natural Science Foundation of China (20671037, 20371018)
文摘The mRNA of insulin receptor (IR), the insulin receptor substrates (IRSs), glucose transporter 2 (GLUT2) and glucokinase (GK) in alloxan-induced diabetic rat livers were amplified by RT-PCR. The protein of the insulin receptor in rat livers was determined by westem-blotting. The results show that IR expression level decreased at the level of mRNA and protein. The gene expressions of IRSs, GLUT2 and GK changed significantly. The hepatic glycogen content in alloxan-diabetic rats treated with insulin ((13.2 ± 0.4) mg·g^-1) did not restore to normal level ((17.0 ±0.4) mg·g^-1) by means of anthrone-H2SO4 methods. The results imply that insulin resistance is developed during inchoate phase of alloxan-induced diabetic rats.
基金supported by the National Natural Science Foundation of China(No.41174158)the National Commonwealth Research Project of China(No.201011081-4)
文摘In this letter, we investigate quasi-cyclic low-density parity-check (QC-LDPC) codes in a 40-Gb/s nonreturn-to-zero differential phase-shift keying (NRZ-DPSK) signal transmission system based on a fiber- based optical parametric amplifier (FOPA). A constructed algorithm of QC-LDPC codes according to the optimizing set of shift vMues on the circulant permutation matrix (CPM) of the basis matrix is proposed. Simulation results prove that the coding gain in the encoded system can be realized at 10.2 dB under QC- LDPC codes with a code rate of 5/6 when the bit error rate (BER) is 10-9. In addition, the error-floor level originating from the uncoded system is suppressed.
文摘The wireless communication system's performance is greatly constrained by the wireless channel characteristics,especially in some specific environment.Therefore,signal transmission will be greatly impacted even if not in a complicated topography.Testing results show that it is hardly to characterize the radio propagation properties for the antenna installed on the ground.In order to ensure a successful communication,the radio frequency(RF)wireless signal intensity monitor system was designed.We can get the wireless link transmission loss through measuring signal strength from received node.The test shows that the near-ground wireless signal propagation characteristics still can be characterized by the log distance propagation loss model.These results will conduce to studying the transmission characteristic of Near-Earth wireless signals and will predict the coverage of the earth's surface wireless sensor network.
基金High-Tech Research and DevelopmentProgram of China (No. 2003AA123310)
文摘OAM (Operations, Administration and Maintenance) system is a very impo rtant component of 3G cellular network. In order to acquire overall managemen t, fast response and steady operation, an SCTP (Stream Control Transmission Prot ocol) based OAM, i.e., SOAM system was proposed. SOAM implements new characters of SCTP such as multi-stream, enforced SACK and heartbeat mechanism on its tran sport layer. These characters help SOAM decrease the message transmission delay and accelerate the link failure detection. Besides, a new component named SOAM agent was introduced to improve the operation efficiency of SOAM. The experim ental results prove the proposed SOAM system achieves better performance on sign aling transmission compared with conventional TCP based OAM system.
基金supported by the National Natural Science Foundation of China(60572098)
文摘A new monostatic array system taking advantage of diverse waveforms to improve the performance of underwater tar- get localization is proposed. Unlike the coherent signals between different elements in common active array, the transmitted signals from different elements here are spatially orthogonal waveforms which allow for array processing in the transit mode and result in an extension of array aperture. The mathematical derivation of Capon estimator for this sonar system is described in detail. And the performance of this orthogonal-waveform based sonar is an- alyzed and compared with that of its phased-array counterpart by water tank experiments. Experimental results show that this sonar system could achieve 12 dB-15 dB additional array gain over its phased-array counterpart, which means a doubling of maximum detection range. Moreover, the angular resolution is significantly improved at lower SNR.
基金Supported by the National Natural Science Foundation of China (No.60804064,60772006)
文摘This paper investigates the problem of real-time estimation for one kind of linear time invariant systems which subject to limited communication capacity. The communication limitations include signal transmission delay, the out-of-sequence measurements and data packet dropout, which appear typically in a network environment. The kernel of filter design is equally to formularize the traditional Kalman filter as one linear weighted summation which is composed of the initial state estimate and all sequential sampled measurements. For it can adapt aforementioned information limitations, the linear weighted summation is then decomposed into two stages. One is a predict-estimator composed by all reached measurements, another is one compensator constructed by those time-delayed data. In the network environment, there are obvious differences between the new hybrid filter and those existing delayed Kalman filters. For example, the novel filter can be optimal in the sense of linear minimum mean square error as soon as all measurements available and has the lowest running time than these existing delayed filters. One simulation, including two cases, is utilized to illustrate the design procedures proposed in this paper.
基金The Research and Development for Further Advancement of the 5th Generation Mobile Communication System(No.JP1000254)。
文摘Ultra-densification of radio access network(RAN)is a key to efficiently support the exponentially growing mobile data traffic in 5 G era.Furthermore,extremely high frequency band like mm Wave band was utilized to solve the bandwidth shortage problem.However,untra-dense reusing the same radio resource produced severe interference.And the mm Wave link was very harsh due to frequent blockage by obstacles.Therefore a new RAN architecture needed to be introduced to realize ultra-reliable communications in such a severe radio propagation environment.An architecture of distributed MIMO based RAN was presented.Then,enhanced interference coordination(e IC)was described.Finally,the effectiveness of distributed MIMO based RAN with e IC by computer simulation was showed.
基金supported by a grant from the national High Technology Research and development Program of China (863 Program) (No.2012AA01A502)National Natural Science Foundation of China (No.61179006)Science and Technology Support Program of Sichuan Province(No.2014GZX0004)
文摘The problem of underdetermined blind source separation of adjacent satellite interference is proposed in this paper. Density Clustering algorithm(DC-algorithm) presented in this article is different from traditional methods. Sparseness representation has been applied in underdetermined blind signal source separation. However, some difficulties have not been considered, such as the number of sources is unknown or the mixed matrix is ill-conditioned. In order to find out the number of the mixed signals, Short Time Fourier Transform(STFT) is employed to segment received mixtures. Then, we formulate the blind source signal as cluster problem. Furthermore, we construct Cost Function Pair and Decision Coordinate System by using density clustering. At the end of this paper, we discuss the performance of the proposed method and verify the novel method based on several simulations. We verify the proposed method on numerical experiments with real signal transmission, which demonstrates the validity of the proposed method.
文摘Based on the former research results of the influence of contact failure in ideal and unmatched circuits, this paper further studies theoretically the effects of contact failure on the digital signal transmission in the lossy circuits, which may happen widely in practical applications. Experiences show that even in high-quality lines, losses deform the voltage and current wave shapes owing to their effects on the amplitude of the various waves making up the over-all line voltage and current. Although the derivations show that the effects of contact failure in the lossy circuits on the signal transmission are quite complicated. The probability of occurrence of error codes can be increased significantly.