Terahertz time-domain spectroscopy(THz-TDS)system,as a new means of spectral analysis and detection,plays an increasingly pivotal role in basic scientific research.However,owing to the long scanning time of the tradit...Terahertz time-domain spectroscopy(THz-TDS)system,as a new means of spectral analysis and detection,plays an increasingly pivotal role in basic scientific research.However,owing to the long scanning time of the traditional THz-TDS system and the complex control of the asynchronous optical scanning(ASOPS)system,which requires frequent calibration,we combine traditional THz-TDS and ASOPS systems to form a composite system and propose an all-fiber trigger signal generation method based on the time overlapping interference signal generated by the collinear motion of two laser pulses.Finally,the time-domain and frequency-domain spectra are obtained by using two independent systems in the integrated systems.It is found that the full width at half maximum(FWHM)of the time-domain spectra and the spectral width of the frequency-domain spectra are almost the same,but the sampling speed of the ASOPS system is significantly faster than that of the traditional THz-TDS system,which conduces to the study of the transient characteristics of substances.展开更多
In this paper we propose a new class of ternary Zero Correlation Zone (ZCZ) sequence sets based on binary ZCZ sequence sets construction. It is shown that the proposed ternary ZCZ sequence sets can reach the upper bou...In this paper we propose a new class of ternary Zero Correlation Zone (ZCZ) sequence sets based on binary ZCZ sequence sets construction. It is shown that the proposed ternary ZCZ sequence sets can reach the upper bound on the ZCZ sequences. The performance of the proposed sequences set in asynchronous Direct Sequence-Code Division Multiple Access (DS-CDMA) system is evaluated. In the simulation we used two types of channels: Additive White Gaussian Noise (AWGN) and frequency non-selective fading with AWGN noise. The proposed ternary ZCZ sequence sets show better results, in term of Bit Error Rate (BER), than Hayashi’s ternary ZCZ sequence sets.展开更多
描述了一种基于现场可编程逻辑阵列(FPGA)的高速核信号采集系统的设计方案。FPGA作为控制核心,实现对高速Analog-to-Digital Converter(ADC)和Universal Serial Bus(USB)的逻辑控制和数字信号的采样、滤波、甄别、存储、传输处理,并使...描述了一种基于现场可编程逻辑阵列(FPGA)的高速核信号采集系统的设计方案。FPGA作为控制核心,实现对高速Analog-to-Digital Converter(ADC)和Universal Serial Bus(USB)的逻辑控制和数字信号的采样、滤波、甄别、存储、传输处理,并使用异步First In First Out(FIFO)实现ADC数据采集模块和USB数据传输模块2个不同时钟域之间的数据传输,提高数据的吞吐率。最后利用上位机软件进行数据处理和绘图显示。测试结果表明,该系统能够实现核信号的实时、高效采集。展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2021YFB3200100)the National Natural Science Foundation of China(Grant No.61575131)。
文摘Terahertz time-domain spectroscopy(THz-TDS)system,as a new means of spectral analysis and detection,plays an increasingly pivotal role in basic scientific research.However,owing to the long scanning time of the traditional THz-TDS system and the complex control of the asynchronous optical scanning(ASOPS)system,which requires frequent calibration,we combine traditional THz-TDS and ASOPS systems to form a composite system and propose an all-fiber trigger signal generation method based on the time overlapping interference signal generated by the collinear motion of two laser pulses.Finally,the time-domain and frequency-domain spectra are obtained by using two independent systems in the integrated systems.It is found that the full width at half maximum(FWHM)of the time-domain spectra and the spectral width of the frequency-domain spectra are almost the same,but the sampling speed of the ASOPS system is significantly faster than that of the traditional THz-TDS system,which conduces to the study of the transient characteristics of substances.
文摘In this paper we propose a new class of ternary Zero Correlation Zone (ZCZ) sequence sets based on binary ZCZ sequence sets construction. It is shown that the proposed ternary ZCZ sequence sets can reach the upper bound on the ZCZ sequences. The performance of the proposed sequences set in asynchronous Direct Sequence-Code Division Multiple Access (DS-CDMA) system is evaluated. In the simulation we used two types of channels: Additive White Gaussian Noise (AWGN) and frequency non-selective fading with AWGN noise. The proposed ternary ZCZ sequence sets show better results, in term of Bit Error Rate (BER), than Hayashi’s ternary ZCZ sequence sets.
文摘为降低车用异步电机控制系统研发成本,缩短开发周期,提高开发效率,设计了一种基于TMS320F28335微控制器和矢量控制(field oriented control,FOC)算法的车用异步电机闭环控制实验平台。实验平台通过MATLAB/Simulink与TI系列数字信号处理器(digital signal processing,DSP)开发板无缝连接实现代码生成,省去复杂的C语言代码编写,将生成代码的程序自动通过CCS6.2软件载入微处理器TMS320F28335开发板中,控制车用异步电机运行,并运用Labview软件对车用异步电机系统运行数据进行实时监控并在线修改。实验结果表明,该实验平台能够实现车用异步电机矢量控制系统的性能测试,有效缩短异步电机控制器的开发周期,提高了系统开发效率,节省了研制成本。
文摘描述了一种基于现场可编程逻辑阵列(FPGA)的高速核信号采集系统的设计方案。FPGA作为控制核心,实现对高速Analog-to-Digital Converter(ADC)和Universal Serial Bus(USB)的逻辑控制和数字信号的采样、滤波、甄别、存储、传输处理,并使用异步First In First Out(FIFO)实现ADC数据采集模块和USB数据传输模块2个不同时钟域之间的数据传输,提高数据的吞吐率。最后利用上位机软件进行数据处理和绘图显示。测试结果表明,该系统能够实现核信号的实时、高效采集。
