A method of describing one-dimensional photonic crystals （1DPCs） based on Z-domain digital signal processing theory is presented. The analytical expression of the target band gap spectrum in the digital domain is ob...A method of describing one-dimensional photonic crystals （1DPCs） based on Z-domain digital signal processing theory is presented. The analytical expression of the target band gap spectrum in the digital domain is obtained by the autocorrelation of its impulse response. The feasibility of this method is verified by reconstructing two simple 1DPC structures with a target photonic band gap obtained by the traditional transfer matrix method. This method provides an effective approach to function-guided designs of interference-based band gap structures for photonic applications.展开更多
In this paper, we investigate advanced digital signal process ing （DSP） at the transmitter and receiver side for signal pre equalization and postequalization in order to improve spec trum efficiency （SE） and trans...In this paper, we investigate advanced digital signal process ing （DSP） at the transmitter and receiver side for signal pre equalization and postequalization in order to improve spec trum efficiency （SE） and transmission distance in an optical access network. A novel DSP scheme for this optical super Nyquist filtering 9 Quadrature Amplitude Modulation （9 QAM） like signals based on muhimodulus equalization with out post filtering is proposed. This scheme recovers the Ny quist filtered Quadrature PhaseShift Keying （QPSK） signal to a 9QAMlike one. With this technique, SE can be increased to 4 b/s/Hz for QPSK signals. A novel digital superNyquist signal generation scheme is also proposed to further suppress the Nyquist signal bandwidth and reduce channel crosstalk without the need for optical prefiltering. Only optical cou plers are needed for superNyquist wavelengthdivisionmulti plexing （WDM） channel multiplexing. We extend the DSP for shorthaul optical transmission networks by using highorder QAMs. We propose a highspeed Can＇ierless Amplitude/Phase 64 QAM （CAP64 QAM） system using directly modulated la ser （DML） based on direct detection and digital equalization. Decisiondirected least mean square is used to equalize the CAP64QAM. Using this scheme, we generate and transmit up to 60 Gbit/s CAP64QAM over 20 km standard single mode fiber based on the DML and direct detection. Finally, several key problems are solved for real time orthogonalfre quencydivisionmultiplexing （OFDM） signal transmission aml processing. With coherent detection, up to 100 Glfit/s 16 QAMOFDM realtime transmission is possible.展开更多
A discrete model reference adaptive controller of robot arm is obtained by integrating the reduced dynamic model of robot, model reference adaptive control （MRAC） and digital signal processing （DSP） computer syste...A discrete model reference adaptive controller of robot arm is obtained by integrating the reduced dynamic model of robot, model reference adaptive control （MRAC） and digital signal processing （DSP） computer system into an electromechanical system. With the DSP computer system, the control signal of each joint of the robot arm can be processed in real time and independently. The simulation and experiment results show that with the control strategy, the robot achieved a good trajectory following precision, a good decoupling performance and a high real-time adaptivity.展开更多
In recent years, explosively increasing data traffic has been boosting the con?tinuous demand of high speed optical interconnection inside or among data centers, high performance computers and even consumer electronic...In recent years, explosively increasing data traffic has been boosting the con?tinuous demand of high speed optical interconnection inside or among data centers, high performance computers and even consumer electronics. To pursue the improved intercon?nection performance of capacity, energy efficiency and simplicity, effective approaches are demonstrated including particularly advanced digital signal processing (DSP) meth?ods. In this paper, we present a review about the enabling adaptive DSP methods for opti?cal interconnection applications, and a detailed summary of our recent and ongoing works in this field. In brief, our works focus on dealing with the specific issues for short-reach interconnection scenarios with adaptive operation, including signal-to-noise-ratio (SNR) limitation, level nonlinearity distortion, energy efficiency consideration and the de?cision precision.展开更多
This fully digital beam position measurement instrument is designed for beam position monitoring and machine research in Shanghai Synchrotron Radiation Facility. The signals received from four position-sensitive detec...This fully digital beam position measurement instrument is designed for beam position monitoring and machine research in Shanghai Synchrotron Radiation Facility. The signals received from four position-sensitive detectors are narrow pulses with a repetition rate up to 499.654 MHz and a pulse width of around 100 ps, and their dynamic range could vary over more than 40 dB in machine research. By the employment of the under-sampling technique based on high-speed high-resolution A/D conversion, all the processing procedure is performed fully by the digital signal processing algorithms integrated in one single Field Programmable Gate Array. This system functions well in the laboratory and commissioning tests, demonstrating a position resolution (at the turn by turn rate of 694 kHz) better than 7 μm over the input amplitude range of -40 dBm to 10 dBm which is well beyond the requirement.展开更多
The heavy-ion accelerator facility(HIAF)under construction in China will produce various stable and intense radioactive beams with energies ranging from MeV/u to GeV/u.The ion-linac(iLinac)accelerator,which will serve...The heavy-ion accelerator facility(HIAF)under construction in China will produce various stable and intense radioactive beams with energies ranging from MeV/u to GeV/u.The ion-linac(iLinac)accelerator,which will serve as the injector for the HIAF,is a superconducting heavy-ion accelerator containing 13 cryomodules.It will operate in either continuous wave mode or pulsed mode,with a beam current ranging from 0.01 to 1 emA.The beam position monitor(BPM)is crucial for this high-beam-power machine,which requires precise beam control and a very small beam loss of less than 1 W/m,especially inside the cryomodules of this unique beam instrument.Nearly 70 BPMs will be installed on the iLinac.New digital beam position and phase measurement(DBPPM)electronics based on a heterogeneous multiprocessing platform system-on-chip(MPSoC)has been developed to provide accurate beam trajectory and phase measurements as well as beam interlocking signals for a fast machine protection system(MPS).The DBPPM comprises an analog front-end(AFE)board in field programmable gate array(FPGA)mezzanine-connector(FMC)form factor,along with a digital signal processing board housed within a “2U 19”chassis.To mitigate radio frequency(RF)leakage effects from high-power RF systems in certain scenarios,beam signals undergo simultaneous processing at both fundamental and second-harmonic frequencies.A dynamic range from-65 dBm to 0 dBm was established to accommodate both weak beam commissioning and high-intensity operational demands.Laboratory tests demonstrated that at input power levels exceeding-45 d Bm,the phase resolution surpasses 0.05°,and the position resolution exceeds 5μm.These results align well with the stipulated measurement requirements.Moreover,the newly developed DBPPM has self-testing and self-calibration functions that are highly helpful for the systematic evaluation of numerous electronic components and fault diagnosis equipment.In addition,the DBPPM electronics implements a 2D nonlinear polynomial correction on the FPGA and can collect accurate real-time position measurements at large beam offsets.This newly developed DBPPM electronics has been applied to several Linac machines,and the results from beam measurements show high performance,good long-term stability,and high reliability.In this paper,a detailed overview of the architecture,performance,and proof-of-principle measurement of the beams is presented.展开更多
A principle and method of constructing the digital acquisition system is presented in this work,which is convenient for the study on the theories and algorithms of digital nuclear signal processing.The hardware system...A principle and method of constructing the digital acquisition system is presented in this work,which is convenient for the study on the theories and algorithms of digital nuclear signal processing.The hardware system of the digital acquisition system consists of front-end controller,waveform digitizer and PC workstation,on which the software system has been developed based on Visual C++under Windows environment.The alterable-frequency sampling(AFS)algorithm and the alterable-frequency trapezoidal filter(AFTF)algorithm have also been studied in the real-time environment,along with a digital nuclear spectrum acquisition system being set up based on the new algorithms and theγ-ray spectra of 241Am being shown.A useful experimental platform could be provided by this work for the successive work such as the development of global digitized nuclear measurement system and the study of digital nuclear signal processing.展开更多
In this paper, we present an optimized design method for high-speed embedded image processing system using 32 bit floating-point Digital Signal Processor （DSP） and Complex Programmable Logic Device （CPLD）. The DSP...In this paper, we present an optimized design method for high-speed embedded image processing system using 32 bit floating-point Digital Signal Processor （DSP） and Complex Programmable Logic Device （CPLD）. The DSP acts as the main processor of the system： executes digital image processing algorithms and operates other devices such as image sensor and CPLD. The CPLD is used to acquire images and achieve complex logic control of the whole system. Some key technologies are introduced to enhance the performance of our system. In particular, the use of DSP/BIOS tool to develop DSP applications makes our program run much more efficiently. As a result, this system can provide an excellent computing platform not only for executing complex image processing algorithms, but also for other digital signal processing or multi-channel data collection by choosing different sensors or Analog-to-Digital （A/D） converters.展开更多
Programmable photonic waveguide meshes can be programmed into many different circuit topologies and thereby provide a variety of functions.Due to the complexity of the signal routing in a general mesh,a particular syn...Programmable photonic waveguide meshes can be programmed into many different circuit topologies and thereby provide a variety of functions.Due to the complexity of the signal routing in a general mesh,a particular synthesis algorithm often only accounts for a specific function with a specific cell configuration.In this paper,we try to synthesize the programmable waveguide mesh to support multiple configurations with a more general digital signal processing platform.To show the feasibility of this technique,photonic waveguide meshes in different configurations(square,triangular and hexagonal meshes)are designed to realize optical signal interleaving with arbitrary duty cycles.The digital signal processing(DSP)approach offers an effective pathway for the establishment of a general design platform for the software-defined programmable photonic integrated circuits.The use of well-developed DSP techniques and algorithms establishes a link between optical and electrical signals and makes it convenient to realize the computer-aided design of optics–electronics hybrid systems.展开更多
Pulse shaping,which improves signal-to-noise ratio excellently,has been extensively used in nuclear signal processing.This paper presents a cusp-like pulse-shaping technique developed through the recursive difference ...Pulse shaping,which improves signal-to-noise ratio excellently,has been extensively used in nuclear signal processing.This paper presents a cusp-like pulse-shaping technique developed through the recursive difference equation in time domain.It can be implemented in field programmable gate array hardware system.Another flat-topped cusp-like shaper is developed to optimize the time constant of pulse shaping and reduce the influence of ballistic deficit.The methods of both baseline restoration and pile-up rejection are described.The ^(137)Cs energy spectra measured with the digital cusp-like shaper are 6.6% energy resolution,while those by traditional analog pulse shaper are 7.2% energy resolution,under the same conditions.This technique offers flexibility,too,in adjusting the pulse shaper parameters.展开更多
A cross-correlation detection method to process backscatter signals of multi-laser beams measuring （MLBM） is presented, which can be firstly filtered by the digital filter composed of average median filter and finit...A cross-correlation detection method to process backscatter signals of multi-laser beams measuring （MLBM） is presented, which can be firstly filtered by the digital filter composed of average median filter and finite impulse response （FIR） digital filter. The processing of backscatter signals using single-pulse and three-pulse cross-correlation detection methods is depicted in detail. From calculation results, the multi-pulse cross-correlation detection could effectively improve signal-to-noise ratio （SNR）. Finally, both wind velocity and direction are determined by the peak-delay method based on the correlation function which shows high measuring precision and high SNR of the MLBM system with the assistance of the digital cross- correlation detection.展开更多
为实现星载数字时间延迟积分(Digital Time Integration Delay,DTDI)系统的有效设计与成像质量分析,文章提出星载DTDI系统全链路成像质量影响因素分析方法。首先,分析了技术的原理和影响因素,在此基础上构建了场景-大气-星载系统-处理...为实现星载数字时间延迟积分(Digital Time Integration Delay,DTDI)系统的有效设计与成像质量分析,文章提出星载DTDI系统全链路成像质量影响因素分析方法。首先,分析了技术的原理和影响因素,在此基础上构建了场景-大气-星载系统-处理的全链路DTDI成像系统仿真模型,开展了多要素影响下的DTDI成像仿真试验与分析评价。结果表明:0.9 m分辨率下,积分时间0.063 ms、量化位数12 bit、TDI级数6级可以获得较好的成像质量,利用DTDI技术可将平台稳定度要求降至0.1(°)/s。文章研究成果可为星载DTDI系统设计分析提供参考。展开更多
An adaptive dispersion estimation(ADE)is proposed to compensate dispersion and estimate the transfer function of the fiber channel with GerchbergSaxton(G-S)algorithm,using the stochastic gradient descent(SGD)method in...An adaptive dispersion estimation(ADE)is proposed to compensate dispersion and estimate the transfer function of the fiber channel with GerchbergSaxton(G-S)algorithm,using the stochastic gradient descent(SGD)method in the intensity-modulation and direct-detection(IM-DD)system,improving the tolerance of the algorithm to chromatic dispersion(CD).In order to address the divergence arising from the perturbation in the amplitude of the received signal caused by the filtering effect of the non-ideal channels,a channel-compensation equalizer(CCE)derived from the back-to-back(BTB)scenario is employed at the transmitter to make the amplitude of the received signal depicting the CD effect more accurately.The simulation results demonstrate the essentiality of CCE for the convergence and performance improvement of the G-S algorithm.Results show that it supports 112Gb/s four-level pulse amplitude modulation(PAM4)over 100 km standard single-mode fiber(SSMF)transmission under the 7%forward error correction(FEC)threshold of 3.8E-3.Besides,ADE improves the tolerance to wavelength drift from about 4 nm to 42 nm,and there is a better tolerance for fiber distance perturbation,indicating the G-S algorithm and its derived algorithms with the ADE scheme exhibit superior robustness to the perturbation in the system.展开更多
基于数字信号处理(Digital Signal Processing,DSP)技术,研究播音主持声音处理的关键技术,包括预处理与降噪、音色美化与均衡、动态范围控制。实验表明,应用基于DSP技术的播音主持声音处理技术,可使播音主持的声音更加清晰、悦耳且稳定...基于数字信号处理(Digital Signal Processing,DSP)技术,研究播音主持声音处理的关键技术,包括预处理与降噪、音色美化与均衡、动态范围控制。实验表明,应用基于DSP技术的播音主持声音处理技术,可使播音主持的声音更加清晰、悦耳且稳定,有效提高不同场景下的声音质量。展开更多
随着广播电视行业的快速发展,音频信号的质量成为提升视听体验的关键因素。传统音频处理方法已无法满足现代广播电视系统对音频清晰度、动态范围及噪声控制的高要求,数字信号处理(Digital Signal Processing,DSP)技术以其强大的计算能...随着广播电视行业的快速发展,音频信号的质量成为提升视听体验的关键因素。传统音频处理方法已无法满足现代广播电视系统对音频清晰度、动态范围及噪声控制的高要求,数字信号处理(Digital Signal Processing,DSP)技术以其强大的计算能力和灵活的处理方式成为解决此问题的有效手段。重点研究DSP技术在广播电视音频信号处理中的优化措施,探讨优化噪声抑制算法、动态范围压缩、增强音频均衡处理以及集成回声消除算法等技术的融合应用。这些技术的有效结合能够显著减少噪声对音频质量的干扰,精确检测音频信号的动态变化,确保音频信号的均衡,并有效消除音频信号中的回声。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10804070 and 61137002)the Key Program of the Science and Technology Commission of Shanghai,China(Grant No.11jc1413300)the Shanghai Leading Academic Discipline Project,China(Grant No.S30108)
文摘A method of describing one-dimensional photonic crystals （1DPCs） based on Z-domain digital signal processing theory is presented. The analytical expression of the target band gap spectrum in the digital domain is obtained by the autocorrelation of its impulse response. The feasibility of this method is verified by reconstructing two simple 1DPC structures with a target photonic band gap obtained by the traditional transfer matrix method. This method provides an effective approach to function-guided designs of interference-based band gap structures for photonic applications.
基金supported by the High Technology Research and Development Program of China("863"Program)under Grant No.2012AA011303 and 2013AA010501National Nature Science Foundation of China under Grant No.61325002
文摘In this paper, we investigate advanced digital signal process ing （DSP） at the transmitter and receiver side for signal pre equalization and postequalization in order to improve spec trum efficiency （SE） and transmission distance in an optical access network. A novel DSP scheme for this optical super Nyquist filtering 9 Quadrature Amplitude Modulation （9 QAM） like signals based on muhimodulus equalization with out post filtering is proposed. This scheme recovers the Ny quist filtered Quadrature PhaseShift Keying （QPSK） signal to a 9QAMlike one. With this technique, SE can be increased to 4 b/s/Hz for QPSK signals. A novel digital superNyquist signal generation scheme is also proposed to further suppress the Nyquist signal bandwidth and reduce channel crosstalk without the need for optical prefiltering. Only optical cou plers are needed for superNyquist wavelengthdivisionmulti plexing （WDM） channel multiplexing. We extend the DSP for shorthaul optical transmission networks by using highorder QAMs. We propose a highspeed Can＇ierless Amplitude/Phase 64 QAM （CAP64 QAM） system using directly modulated la ser （DML） based on direct detection and digital equalization. Decisiondirected least mean square is used to equalize the CAP64QAM. Using this scheme, we generate and transmit up to 60 Gbit/s CAP64QAM over 20 km standard single mode fiber based on the DML and direct detection. Finally, several key problems are solved for real time orthogonalfre quencydivisionmultiplexing （OFDM） signal transmission aml processing. With coherent detection, up to 100 Glfit/s 16 QAMOFDM realtime transmission is possible.
文摘A discrete model reference adaptive controller of robot arm is obtained by integrating the reduced dynamic model of robot, model reference adaptive control （MRAC） and digital signal processing （DSP） computer system into an electromechanical system. With the DSP computer system, the control signal of each joint of the robot arm can be processed in real time and independently. The simulation and experiment results show that with the control strategy, the robot achieved a good trajectory following precision, a good decoupling performance and a high real-time adaptivity.
基金This work was supported by National Natural Science Foundation of Chi⁃na(NSFC)under Grant Nos.61935011,61875124 and 61875049.
文摘In recent years, explosively increasing data traffic has been boosting the con?tinuous demand of high speed optical interconnection inside or among data centers, high performance computers and even consumer electronics. To pursue the improved intercon?nection performance of capacity, energy efficiency and simplicity, effective approaches are demonstrated including particularly advanced digital signal processing (DSP) meth?ods. In this paper, we present a review about the enabling adaptive DSP methods for opti?cal interconnection applications, and a detailed summary of our recent and ongoing works in this field. In brief, our works focus on dealing with the specific issues for short-reach interconnection scenarios with adaptive operation, including signal-to-noise-ratio (SNR) limitation, level nonlinearity distortion, energy efficiency consideration and the de?cision precision.
基金Supported by Knowledge Innovation Program of The Chinese Academy of Sciences (KJCX2-YW-N27)the National Natural Science Foundation of China (10875119)100 Talents Program of The Chinese Academy of Sciences
文摘This fully digital beam position measurement instrument is designed for beam position monitoring and machine research in Shanghai Synchrotron Radiation Facility. The signals received from four position-sensitive detectors are narrow pulses with a repetition rate up to 499.654 MHz and a pulse width of around 100 ps, and their dynamic range could vary over more than 40 dB in machine research. By the employment of the under-sampling technique based on high-speed high-resolution A/D conversion, all the processing procedure is performed fully by the digital signal processing algorithms integrated in one single Field Programmable Gate Array. This system functions well in the laboratory and commissioning tests, demonstrating a position resolution (at the turn by turn rate of 694 kHz) better than 7 μm over the input amplitude range of -40 dBm to 10 dBm which is well beyond the requirement.
基金supported by the National Natural Science Foundation of China(No.11975290)。
文摘The heavy-ion accelerator facility(HIAF)under construction in China will produce various stable and intense radioactive beams with energies ranging from MeV/u to GeV/u.The ion-linac(iLinac)accelerator,which will serve as the injector for the HIAF,is a superconducting heavy-ion accelerator containing 13 cryomodules.It will operate in either continuous wave mode or pulsed mode,with a beam current ranging from 0.01 to 1 emA.The beam position monitor(BPM)is crucial for this high-beam-power machine,which requires precise beam control and a very small beam loss of less than 1 W/m,especially inside the cryomodules of this unique beam instrument.Nearly 70 BPMs will be installed on the iLinac.New digital beam position and phase measurement(DBPPM)electronics based on a heterogeneous multiprocessing platform system-on-chip(MPSoC)has been developed to provide accurate beam trajectory and phase measurements as well as beam interlocking signals for a fast machine protection system(MPS).The DBPPM comprises an analog front-end(AFE)board in field programmable gate array(FPGA)mezzanine-connector(FMC)form factor,along with a digital signal processing board housed within a “2U 19”chassis.To mitigate radio frequency(RF)leakage effects from high-power RF systems in certain scenarios,beam signals undergo simultaneous processing at both fundamental and second-harmonic frequencies.A dynamic range from-65 dBm to 0 dBm was established to accommodate both weak beam commissioning and high-intensity operational demands.Laboratory tests demonstrated that at input power levels exceeding-45 d Bm,the phase resolution surpasses 0.05°,and the position resolution exceeds 5μm.These results align well with the stipulated measurement requirements.Moreover,the newly developed DBPPM has self-testing and self-calibration functions that are highly helpful for the systematic evaluation of numerous electronic components and fault diagnosis equipment.In addition,the DBPPM electronics implements a 2D nonlinear polynomial correction on the FPGA and can collect accurate real-time position measurements at large beam offsets.This newly developed DBPPM electronics has been applied to several Linac machines,and the results from beam measurements show high performance,good long-term stability,and high reliability.In this paper,a detailed overview of the architecture,performance,and proof-of-principle measurement of the beams is presented.
基金Supported by National Natural Science Foundation of China(NSFC)projects(No.1075111)
文摘A principle and method of constructing the digital acquisition system is presented in this work,which is convenient for the study on the theories and algorithms of digital nuclear signal processing.The hardware system of the digital acquisition system consists of front-end controller,waveform digitizer and PC workstation,on which the software system has been developed based on Visual C++under Windows environment.The alterable-frequency sampling(AFS)algorithm and the alterable-frequency trapezoidal filter(AFTF)algorithm have also been studied in the real-time environment,along with a digital nuclear spectrum acquisition system being set up based on the new algorithms and theγ-ray spectra of 241Am being shown.A useful experimental platform could be provided by this work for the successive work such as the development of global digitized nuclear measurement system and the study of digital nuclear signal processing.
基金Supported by the National Natural Science Foundation of China (No.60472046)
文摘In this paper, we present an optimized design method for high-speed embedded image processing system using 32 bit floating-point Digital Signal Processor （DSP） and Complex Programmable Logic Device （CPLD）. The DSP acts as the main processor of the system： executes digital image processing algorithms and operates other devices such as image sensor and CPLD. The CPLD is used to acquire images and achieve complex logic control of the whole system. Some key technologies are introduced to enhance the performance of our system. In particular, the use of DSP/BIOS tool to develop DSP applications makes our program run much more efficiently. As a result, this system can provide an excellent computing platform not only for executing complex image processing algorithms, but also for other digital signal processing or multi-channel data collection by choosing different sensors or Analog-to-Digital （A/D） converters.
文摘Programmable photonic waveguide meshes can be programmed into many different circuit topologies and thereby provide a variety of functions.Due to the complexity of the signal routing in a general mesh,a particular synthesis algorithm often only accounts for a specific function with a specific cell configuration.In this paper,we try to synthesize the programmable waveguide mesh to support multiple configurations with a more general digital signal processing platform.To show the feasibility of this technique,photonic waveguide meshes in different configurations(square,triangular and hexagonal meshes)are designed to realize optical signal interleaving with arbitrary duty cycles.The digital signal processing(DSP)approach offers an effective pathway for the establishment of a general design platform for the software-defined programmable photonic integrated circuits.The use of well-developed DSP techniques and algorithms establishes a link between optical and electrical signals and makes it convenient to realize the computer-aided design of optics–electronics hybrid systems.
基金supported by the National Natural Science Foundation of China(Nos.41474159 and 41504139)Sichuan Youth Science and Technology Foundation(No.2015JQ0035)+1 种基金Sichuan Science and Technology Support Program(No.2017GZ0390)the Key Laboratory of Applied Nuclear Techniques in Geosciences Sichuan(No.gnzds2014006)
文摘Pulse shaping,which improves signal-to-noise ratio excellently,has been extensively used in nuclear signal processing.This paper presents a cusp-like pulse-shaping technique developed through the recursive difference equation in time domain.It can be implemented in field programmable gate array hardware system.Another flat-topped cusp-like shaper is developed to optimize the time constant of pulse shaping and reduce the influence of ballistic deficit.The methods of both baseline restoration and pile-up rejection are described.The ^(137)Cs energy spectra measured with the digital cusp-like shaper are 6.6% energy resolution,while those by traditional analog pulse shaper are 7.2% energy resolution,under the same conditions.This technique offers flexibility,too,in adjusting the pulse shaper parameters.
基金supported by National Natural Science Foundation of China under Grant No. 60425101-1Foundation for Innovative Research Groups of NSFC under Grant No. 60721001
文摘A cross-correlation detection method to process backscatter signals of multi-laser beams measuring （MLBM） is presented, which can be firstly filtered by the digital filter composed of average median filter and finite impulse response （FIR） digital filter. The processing of backscatter signals using single-pulse and three-pulse cross-correlation detection methods is depicted in detail. From calculation results, the multi-pulse cross-correlation detection could effectively improve signal-to-noise ratio （SNR）. Finally, both wind velocity and direction are determined by the peak-delay method based on the correlation function which shows high measuring precision and high SNR of the MLBM system with the assistance of the digital cross- correlation detection.
基金funded by the National Natural Science Foundation of China NSFC,U22A2005 and 62201033theYoung Elite Scientists Sponsorship Program of CIC 2021QNRC001。
文摘An adaptive dispersion estimation(ADE)is proposed to compensate dispersion and estimate the transfer function of the fiber channel with GerchbergSaxton(G-S)algorithm,using the stochastic gradient descent(SGD)method in the intensity-modulation and direct-detection(IM-DD)system,improving the tolerance of the algorithm to chromatic dispersion(CD).In order to address the divergence arising from the perturbation in the amplitude of the received signal caused by the filtering effect of the non-ideal channels,a channel-compensation equalizer(CCE)derived from the back-to-back(BTB)scenario is employed at the transmitter to make the amplitude of the received signal depicting the CD effect more accurately.The simulation results demonstrate the essentiality of CCE for the convergence and performance improvement of the G-S algorithm.Results show that it supports 112Gb/s four-level pulse amplitude modulation(PAM4)over 100 km standard single-mode fiber(SSMF)transmission under the 7%forward error correction(FEC)threshold of 3.8E-3.Besides,ADE improves the tolerance to wavelength drift from about 4 nm to 42 nm,and there is a better tolerance for fiber distance perturbation,indicating the G-S algorithm and its derived algorithms with the ADE scheme exhibit superior robustness to the perturbation in the system.
文摘随着广播电视行业的快速发展,音频信号的质量成为提升视听体验的关键因素。传统音频处理方法已无法满足现代广播电视系统对音频清晰度、动态范围及噪声控制的高要求,数字信号处理(Digital Signal Processing,DSP)技术以其强大的计算能力和灵活的处理方式成为解决此问题的有效手段。重点研究DSP技术在广播电视音频信号处理中的优化措施,探讨优化噪声抑制算法、动态范围压缩、增强音频均衡处理以及集成回声消除算法等技术的融合应用。这些技术的有效结合能够显著减少噪声对音频质量的干扰,精确检测音频信号的动态变化,确保音频信号的均衡,并有效消除音频信号中的回声。
