A new viewpoint and model of neural signal generation and transmission: Signal transmission on unmyelinated neurons

We establish a preliminary model of neural signal generation and transmission based on our previous research,and use this model to study signal transmission on unmyelinated nerves.In our model,the characteristics of neural signals are studied both on a long-time and a short time scale.On the long-time scale,the model is consistent with the circuit model.On the short time scale,the neural system exhibits a THz and infrared electromagnetic oscillation but the energy envelope curve of the rapidly oscillating signal varies slowly.In addition,the numerical method is used to solve the equations of neural signal generation and transmission,and the effects of the temperature on signal transmission are studied.It is found that overly high and overly low temperatures are not conducive to the transmission of neural signals.

A Simple Configuration for 40 Gbit/s CSRZ Signal Generation with Electrical Band-Limiting to Achieve Large Dispersion Tolerance

We present a novel configuration for carrier suppressed return-to-zero (CSRZ) signal generation, which only requires a single stage Mach-Zehnder (MZ) modulator in conjunction with an electrical mixer. Electrical band-limiting is also introduced to increase dispersion tolerance without causing additional penalty due to nonlinear effects in long haul dense wavelength division multiplexed (DWDM) CSRZ systems using conventional launch power levels.

Pulsewidth-tunable CSRZ-DQPSK signal generation using DPMZMs

We show that absorbed and stored electromagnetic energy are proportional to the reflection group delay in highly reflective dispersive dielectric mirrors over the high-reflectivity band.Our theoretical considerations are verified by numerical simulations performed on different dielectric mirror structures.The revealed proportionality between group delay and absorbed energy sets constraint on the application of ultrabroadband and/or dispersive dielectric mirrors in broadband or widely tunable,high-power laser systems.

Photonic-assisted FSK signal generation based on carrier phase-shifted double sideband modulation

An approach to generate high-speed and wideband frequency shift keying(FSK)signals based on carrier phase-shifted double sideband(CPS-DSB)modulation is proposed and experimentally validated.The core part of the scheme is a pair of cascaded polarization-sensitive LiNbO_(3) Mach–Zehnder modulators and phase modulators,whose polarization directions of the principal axes are mutually orthogonal to each other.A proof-of-concept experiment is carried out,where a 0.5 Gb/s FSK signal with the carrier frequencies of 4 and 8 GHz and a 1 Gb/s FSK signal with the carrier frequencies of 8 and 16 GHz are generated successfully.

Photonic generation of ASK microwave signals with SSB format

Optical beating is the usual approach to generation of microwave signals.However,the highest frequency achievable for microwave signals is limited by the bandwidths of optoelectronic devices.To maximize the microwave frequency with a limited bandwidth of a photodetector(PD)and relieve the bandwidth bottleneck,we propose to generate microwave signals with the single sideband(SSB)format by beating a continuous wave(CW)light with an optical SSB signal.By simply adjusting the frequency diference between the CW light and the carrier of the optical SSB signal,the frequency of the generated microwave SSB signal is changed correspondingly.In the experiment,amplitude shift keying(ASK)microwave signals with the SSB format are successfully generated with diferent carrier frequencies and coding bit rates,and the recovered coding information agrees well with the original pseudo random binary sequence(PRBS)of 2^(7)−1 bits.The proposed approach can signifcantly relieve the bandwidth restriction set by optoelectronic devices in high-speed microwave communication systems.

Simulation of large-scale numerical substructure in real-time dynamic hybrid testing

A solution scheme is proposed in this paper for an existing RTDHT system to simulate large-scale finite element （FE） numerical substructures. The analysis of the FE numerical substructure is split into response analysis and signal generation tasks, and executed in two different target computers in real-time. One target computer implements the response analysis task, wherein a large time-step is used to solve the FE substructure, and another target computer implements the signal generation task, wherein an interpolation program is used to generate control signals in a small time-step to meet the input demand of the controller. By using this strategy, the scale of the FE numerical substructure simulation may be increased significantly. The proposed scheme is initially verified by two FE numerical substructure models with 98 and 1240 degrees of freedom （DOFs）. Thereafter, RTDHTs of a single frame-foundation structure are implemented where the foundation, considered as the numerical substructure, is simulated by the FE model with 1240 DOFs. Good agreements between the results of the RTDHT and those from the FE analysis in ABAQUS are obtained.

A HIGH PERFORMANCE UWB LFM WAVEFORM GENERATOR

In this paper, the design and implementation of a high performance Ultra-WideBand (UWB) Linear Frequency Modulation (LFM) waveform generator at Very High Frequency/Ultra High Frequency (VHF/UHF) band are introduced. Firstly, the design ideas for a high performance UWB LFM waveform generator are described. Then, a generation scheme for UWB LFM waveforms is presented according to the baseband digital generation method combining with the bandwidth ex-tension method via frequency doubling. An experimental system has been implemented and tested. The results show that the UWB LFM waveform generator achieves very high performance.

Optimization and Synthesis of RF CMOS Polyphase Filters with Layout Considerations

A novel software tool for optimization and synthesis of RF CMOS polyhase filters(PPFs),PPFOPTIMA,is developed.In the optimization engine,genetic algorithm is adopted to avoid local optima.Experiments on PPFOPTIMA demonstrate that it is an efficient design aid for design and optimization of RF CMOS PPFs.

Multi-threaded code generation from Signal program to OpenMP

The use of multi-core processors will become a trend in safety critical systems. For safe execution of multi- threaded code, automatic code generation from formal spec- ification is a desirable method. Signal, a synchronous lan- guage dedicated for the functional description of safety crit- ical systems, provides soundness semantics for determinis- tic concurrency. Although sequential code generation of Sig- nal has been implemented in Polychrony compiler, deter- ministic multi-threaded code generation strategy is still far from mature. Moreover, existing code generation methods use certain multi-thread library, which limits the cross plat- form executions. OpenMP is an application program inter- face （API） standard for parallel programming, supported by several mainstream compilers from different platforms. This paper presents a methodology translating Signal program to OpenMP-based multi-threaded C code. First, the intermedi- ate representation of the core syntax of Signal using syn- chronous guarded actions is defined. Then, according to the compositional semantics of Signal equations, the Signal pro- gram is synthesized to dependency graph （DG）. After par- allel tasks are extracted from dependency graph, the Signal program can be finally translated into OpenMP-based C code which can be executed on multiple platforms.

Optical Generation of mm-Wave Signal Through Optoelectronic Phase-Locked Loop

In this paper, we propose a scheme for the generation of low phase noise tunable mm-wave signal by bearing two lightwaves in a photodiode. These two lightwaves are made phase coherent by an optoelectronic phase locked loop. Calculated mm-wave power at a frequency of 60 GHz is found to be -4 dBm.

Photonic generation of background-free millimeter-wave ultra-wideband signals

We review the recent progress of photonic generation of millimeter wave （MMW）-ultra-wideband （UWB） signals. To fully satisfy the standard defined by the Federal Communications Commission （FCC）, the baseband signal （background signal） and the residual local oscillator （LO） signal should be well controlled. We discuss several schemes in this work for generating background-free MMW-UWB signals that are fully compliant with the FCC requirement.

Data signal processing via manchester coding-decoding method using chaotic signals generated by PANDA ring resonator

We investigate the nonlinear behaviors of light recognized as chaos during the propagation of Gaussian laser beam inside a nonlinear polarization maintaining and absorption reducing （PANDA） ring resonator system. It aims to generate the nonlinear behavior of light to obtain data in binary logic codes for transmission in fiber optics communication. Effective parameters, such as refractive indices of a silicon waveguide, coupling coefficients （~）, and ring radius ring （R）, can be properly selected to operate the nonlinear behavior. Therefore, the binary coded data generated by the PANDA ring resonator system can be decoded and converted to Manchester codes, where the decoding process of the transmitted codes occurs at the end of the transmission link. The simulation results show that the original codes can be recovered with a high security of signal transmission using the Manchester method.

Evaluation of the performance of linearly frequency modulated signals generated by heterodyning two free-running laser diodes

A method to evaluate the influence of the laser linewidth on the linearly frequency-modulated(LFM)signals generated by heterodyning two free-running laser diodes(LDs)is proposed.The Pearson correlation coefficient between the instantaneous frequency of the generated LFM signal and that of an ideal LFM signal is introduced to quantify the quality of the generated LFM signal.The closed-form solution of the correlation coefficient is given,which shows that the correlation coefficient is determined by the ratio of the LFM signal bandwidth to the square root of the total linewidth of the two LDs when the observation interval is fixed.Simulation results are also given,which proves the correctness of the theoretical results.

All-Optical Signal Processing with Super-Continuum Generated from Optical Fibers

Super-continuum (SC) generated from optical fibers has many attractive applications in optical communication systems. Discussing the mechanism of wideband and flat SC generation, we describe all-optical signal processing that employs the SC.

A millimeter wave linear superposition oscillator in 0.18 m CMOS technology

This paper presents a millimeter wave （mm-wave） oscillator that generates signal at 36.56 GHz. The ram-wave oscillator is realized in a UMC 0.18 μm CMOS process. The linear superposition （LS） technique breaks through the limit of cut-off frequency （JET）, and realizes a much higher oscillation than Jr. Measurement results show that the LS oscillator produces a calibrated 37.17 dBm output power when biased at 1.8 V; the output power of fundamental signal is -10.85 dBm after calibration. The measured phase noise at 1 MHz frequency offset is -112.54 dBc/Hz at the frequency of 9.14 GHz. This circuit can be properly applied to mm-wave communication systems with advantages of low cost and high integration density.

Virtual vibration test rig for fatigue analysis of dozer push arms

To obtain accurate fatigue life results for construction machinery components,acquiring load spectra is crucial,as their authenticity and validity directly determine the precision of the analysis.In working conditions,component attitudes change continuously,but they remain static on the vibration test rig(VTR),so the acquired target signals should match with the actual component attitudes in the driving signal generation.This paper proposes an efficient and economical simulation-based virtual VTR for fatigue analysis of dozers.First,the relationship between the push arm rotation angle and the cylinder stroke is established,since the cylinder strokes can be measured easily in data acquisition experiments.Second,load decomposition is used to determine the attitude relationship between virtual VTR conditions and actual conditions,and target signals are calculated based on this attitude relationship and measured data.According to the system's frequency response function,the driving signals are iterated until the system's response signals converge with the target signals.Finally,the iteratively obtained load spectra are utilized for fatigue life analysis.The results show that the virtual VTR can effectively and accurately obtain the results of fatigue analysis and has engineering application significance.