To solve the difficulty of designing digital impacting filter in the receiver of random-polar modulated Extended Binary Phase Shift Keying with Continuous Phase (CP-EBPSK), a design method based on Quantum-behaved Par...To solve the difficulty of designing digital impacting filter in the receiver of random-polar modulated Extended Binary Phase Shift Keying with Continuous Phase (CP-EBPSK), a design method based on Quantum-behaved Particle Swarm Optimization (QPSO) algorithm is proposed. Firstly, QPSO is introduced elaborately, and the basic flow of QPSO is also given. Then, the demodulation principle of digital impacting filter in the communication system of CP-EBPSK with random-polar is demonstrated, and QPSO is utilized to design the digital impacting filter, which also takes the effect of finite word length into consideration when implemented by hardware. Finally, the proposed method is simulated. Simulation results show that the digital impacting filter designed by new method can derive satisfied demodulation performance.展开更多
In order to obtain variable characteristics,the digital filter's type,number of taps and coefficients should be changed constantly such that the desired frequency-domain characteristics can be obtained.This paper ...In order to obtain variable characteristics,the digital filter's type,number of taps and coefficients should be changed constantly such that the desired frequency-domain characteristics can be obtained.This paper proposes a method for self-programmable variable digital filter(VDF) design based on field programmable gate array(FPGA).We implement a digital filter system by using custom embedded micro-processor,programmable finite impulse response(P-FIR) macro module,coefficient-loader,clock manager and analog/digital(A/D) or digital/analog(D/A) controller and other modules.The self-programmable VDF can provide the best solution for realization of digital filter algorithms,which are the low-pass,high-pass,band-pass and band-stop filter algorithms with variable frequency domain characteristics.The design examples with minimum 1 to maximum 32 taps FIR filter,based on Modelsim post-routed simulation and onboard running on XUPV5-LX110T,are provided to demonstrate the effectiveness of the proposed method.展开更多
A binary tree representation is designed in this paper for optimization of wave digital filter(WDF)implementation.To achieve this,an equivalent WDF model of the original circuit is converted into abinary tree represen...A binary tree representation is designed in this paper for optimization of wave digital filter(WDF)implementation.To achieve this,an equivalent WDF model of the original circuit is converted into abinary tree representation at first.This WDF binary tree can then be transformed to several topologies with the same implication,since the WDF adaptors have a symmetrical behavior on their ports.Because the WDF implementation is related to field programmable gate array(FPGA)resource usage and the cycle time of emulation,choosing aproper binary tree topology for WDF implementation can help balance the complexity and performance quality of an emulation system.Both WDF-FPGA emulation and HSpice simulation on the same circuit are tested.There is no significant difference between these two simulations.However,in terms of time consumption,the WDF-FPGA emulation has an advantage over the other.Our experiment also demonstrates that the optimized WDF-FPGA emulation has an acceptable accuracy and feasibility.展开更多
With the rapid development of wireless systems,the demand for frequency resources has been increasing in recent years.Therefore,it is necessary to consider the high-quality communication method that efficiently utiliz...With the rapid development of wireless systems,the demand for frequency resources has been increasing in recent years.Therefore,it is necessary to consider the high-quality communication method that efficiently utilizes finite frequency resources.In this paper,Single Sideband 16 Pulse Amplitude Modulation(SSB 16PAM)scheme for the uplink communication is proposed.It transmits data in only Lower Sideband(LSB)without extra Hilbert components.Under Additive White Gaussian Noise(AWGN)channel environment,Bit Error Rate(BER)performance of the proposed scheme is superior by 3 dB in terms of Carrier-to-Noise Ratio(CNR)to 256 Quadrature Amplitude Modulation(256QAM)scheme with the same frequency efficiency and the same Peak-to-Average Power Ratio(PAPR).Our proposed scheme employs the original frequency domain filter on the transmitter side to form an ideal spectrum.The configuration of its process is almost similar to Single Carrier-Frequency Division Multiple Access(SC-FDMA),moreover,half of the input data on the frequency domain is removed.The proposed frequency domain filter produces the SSB-modulated spectrum with a roll-off rate of zero without degrading the BER performance.展开更多
Herein,a three-dimensional(3D)inversion method in the frequency domain based on a time–frequency transformation was developed to improve the efficiency of the 3D inversion of transient electromagnetic(TEM)data.The Fo...Herein,a three-dimensional(3D)inversion method in the frequency domain based on a time–frequency transformation was developed to improve the efficiency of the 3D inversion of transient electromagnetic(TEM)data.The Fourier transform related to the electromagnetic response in the frequency and time domains becomes a sine or cosine transform under the excitation of downward-step current.We established a transformation matrix based on the digital fi ltering calculation for the sine transform,and then the frequency domain projection of the TEM data was determined from the linear transformation system using the smoothing constrained least squares inversion method,in which only the imaginary part was used to maintain the TEM data transformation equivalence in the bidirectional projection.Thus,the time-domain TEM inversion problem was indirectly and effectively solved in the frequency domain.In the 3D inversion of the transformed frequency-domain data,the limited-memory Broyden–Fletcher–Goldfarb–Shannoquasi–Newton(L-BFGS)method was used and modifi ed with a restart strategy to adjust the regularization parameter when the algorithm tended to a local minimum.Synthetic data tests showed that our domain transformation method can stably project the TEM data into the frequency domain with very high accuracy;furthe rmore,the 3D inversion of the transformed frequency-domain data is stable,can be used to recover the real resistivity model with an acceptable effi ciency.展开更多
Some fast finite impulse response (FIR) filters use a large number of look-up tables (LUTs) to configure distributed random-access memories (RAMs) and save registers. The distributed RAMs store 2M precomputed sums of ...Some fast finite impulse response (FIR) filters use a large number of look-up tables (LUTs) to configure distributed random-access memories (RAMs) and save registers. The distributed RAMs store 2M precomputed sums of M permuted operands in order to simplify the accumulation, which lays similarity to the solution of Boolean satisfiability (SAT) problem. In this work, a high-speed fault-tolerant FIR digital filter on field programmable gate array (FPGA) is proposed for hardware implementation. A shift register and an RAM are used to arrange the data flow. Generally, an N-tap digital filter only requires N embedded multipliers on FPGA. The better performance is due to high-radix words and low-latency operations. A 32-tap 8-bit FIR digital filter enjoys a throughput of 9.17 MB/s, taking 109 ns to calculate one convolution. In addition, a fault-tolerant scheme by majority logic is used to correct real-time errors within digital filters.展开更多
The digital filters with adjustable frequency-domain characteristics are called variable filters. Variable filters are useful in the applications where their characteristics are required to be changeable during the co...The digital filters with adjustable frequency-domain characteristics are called variable filters. Variable filters are useful in the applications where their characteristics are required to be changeable during the course of signal processing. Generally speaking, the variable frequency responses of a variable filters are the functions of a set of spectral parameters defining the desired frequencyUomain characteristics. In this paper, we first sample the given variable maghtode specifications and use them to construct a multi-dimensional (M - D) specification array, then propose an outer product expansion method for expanding it as the sum of the outer products of vectors. Using the outer product expansion, we can simplify the difficult problem of desighng a variable filter as the easy one that only needs constant 1 - D filter designs and 1 - D polynoIhal approximations. The method can obtain variable filters having arbitrary desired variable magnitude characteristics with a high design acctiracy.展开更多
In order to eliminate the characteristic harmonics in high voltage direct current(HVDC)transmission systems and to simplify the analog controller structure,this paper proposes a new digital controller by adopting an a...In order to eliminate the characteristic harmonics in high voltage direct current(HVDC)transmission systems and to simplify the analog controller structure,this paper proposes a new digital controller by adopting an approximate inverse system control strategy according to the frequency response characteristic of the hybrid power filter.The pro-posed digital controller is implemented with a TMS320C32 DSP,including a series of parallel digital band-pass filters,phase shifters and amplifiers.The results of both simulations based on PSCAD and experiments on a 30 kVA HVDC system prove that the proposed digital control system is sta-ble and efficient for eliminating the harmonics.展开更多
The ongoing transformation of electrical power systems highlights the weaknesses of the protection schemes of traditional devices because they are designed and configured according to traditional characteristics of th...The ongoing transformation of electrical power systems highlights the weaknesses of the protection schemes of traditional devices because they are designed and configured according to traditional characteristics of the system.Therefore,this work proposes a new methodology to study the fault-generated high frequency transient signals in transmission lines through multiresolution analysis.The high frequency components are determined by a new digital filtering technique based on mathematical morphology theory and a spectral energy index.Consequently,wide spectra of signals in the time–frequency domain are obtained.The performance of this method is verified on an electrical power system modeled in ATP-Draw,where simulation and test signals are developed for different locations,fault resistances,inception angles,high frequency noises,sampling frequencies,types of faults,and shapes of the structuring element.The results show the characteristics of the fault such as the traveling wave frequency,location,and starting time.展开更多
Baseflow is an important component of river or streamflow.It plays a vital role in water utilization and management.An improved Eckhardt recursive digital filter(IERDF)is proposed in this study.The key filter paramete...Baseflow is an important component of river or streamflow.It plays a vital role in water utilization and management.An improved Eckhardt recursive digital filter(IERDF)is proposed in this study.The key filter parameter and maximum baseflow index(BFImax)were estimated using the minimum smoothing method to improve baseflow estimation accuracy.The generally considered BFImax of 0.80,0.50 and 0.25 according to the drainage basin’s predominant geological characteristics often leads to significant errors in the regions that have complex subsurface and hydrologic conditions.The IERDF improved baseflow estimation accuracy by avoiding arbitrary parameter values.The proposed method was applied for baseflow separation in the upstream of Yitong River,a tributary of the Second Songhua River,and its performance was evaluated by comparing the results obtained using isotope-tracer data.The performance of IERDF was also compared with nine baseflow separation techniques belonging to filter,BFI and HYSEP methods.The IERDF was also applied for baseflow separation and calculation of rainfall infiltration recharge coefficient at different locations along the Second Songhua River’s mainstream for the period 2000–2016.The results showed that the minimum smoothing method significantly improved BFImax estimation accuracy.The baseflow process line obtained using IEDRF method was consistent with that obtained using isotope 18 O.The IERDF estimated baseflow also showed stability and reliability when applied in the mainstream of the Second Songhua River.The BFI alone in the river showed an increase from the upstream to the downstream.The proportion of baseflow to total flow showed a decrease with time.The intra-annual variability of BFI was different at different locations of the river due to varying climatic conditions and subsurface characteristics.The highest BFI was observed at the middle reaches of the river in summer due to a water surplus from power generation.The research provided valuable information on baseflow characteristics and runoff mode determination,which can be used for water resources assessment and optimization of economic activity distribution in the region.展开更多
Runoff coefficient(C)values are tabulated and enshrined in hydrological engineering.These values are considered to be constant although they may not correspond to reality.In the same catchment,they may vary according ...Runoff coefficient(C)values are tabulated and enshrined in hydrological engineering.These values are considered to be constant although they may not correspond to reality.In the same catchment,they may vary according to intensity,temporal and spatial distribution of precipitation events,humidity condi-tions,soil and land use.This study aimed to analyze extreme events of precipitation and their corre-sponding flows to obtain experimental runoff coefficients(C)and compare them with the tabulated values.The study was conducted in five experimental catchments in the state of S~ao Paulo,Brazil,with different land uses.The runoff coefficients(C)were obtained from the analysis of hydrograms and using a digital filter,which made it possible to separate the direct runoff from the total flow.We observed a different variation in runoff coefficient values between catchments compared to those obtained from the tables.The runoff coefficients had a high correlation with land use.In catchments with original vege-tation cover,such as Cerrado and forest,they varied little among the events analyzed,unlike the catchments where land use is diversified,with predominantly agricultural and urban occupation.展开更多
A wide-range tracking technique for clock and data recovery(CDR) circuit is presented. Compared to the traditional technique, a digital CDR controller with calibration is adopted to extend the tracking range. Because ...A wide-range tracking technique for clock and data recovery(CDR) circuit is presented. Compared to the traditional technique, a digital CDR controller with calibration is adopted to extend the tracking range. Because of the use of digital circuits in the design, CDR is not sensitive to process and power supply variations. To verify the technique, the whole CDR circuit is implemented using 65-nm CMOS technology. Measurements show that the tracking range of CDR is greater than ±6×10-3 at 5 Gb/s. The receiver has good jitter tolerance performance and achieves a bit error rate of <10–12. The re-timed and re-multiplexed serial data has a root-mean-square jitter of 6.7 ps.展开更多
基金Supported by the National Natural Science Foundation of China (No. 60872075)
文摘To solve the difficulty of designing digital impacting filter in the receiver of random-polar modulated Extended Binary Phase Shift Keying with Continuous Phase (CP-EBPSK), a design method based on Quantum-behaved Particle Swarm Optimization (QPSO) algorithm is proposed. Firstly, QPSO is introduced elaborately, and the basic flow of QPSO is also given. Then, the demodulation principle of digital impacting filter in the communication system of CP-EBPSK with random-polar is demonstrated, and QPSO is utilized to design the digital impacting filter, which also takes the effect of finite word length into consideration when implemented by hardware. Finally, the proposed method is simulated. Simulation results show that the digital impacting filter designed by new method can derive satisfied demodulation performance.
基金Science &Technology Plan Foundation of Hunan Province,China(No.2010F3102)Science Research Foundation of Hunan Province,China(No.08C392)
文摘In order to obtain variable characteristics,the digital filter's type,number of taps and coefficients should be changed constantly such that the desired frequency-domain characteristics can be obtained.This paper proposes a method for self-programmable variable digital filter(VDF) design based on field programmable gate array(FPGA).We implement a digital filter system by using custom embedded micro-processor,programmable finite impulse response(P-FIR) macro module,coefficient-loader,clock manager and analog/digital(A/D) or digital/analog(D/A) controller and other modules.The self-programmable VDF can provide the best solution for realization of digital filter algorithms,which are the low-pass,high-pass,band-pass and band-stop filter algorithms with variable frequency domain characteristics.The design examples with minimum 1 to maximum 32 taps FIR filter,based on Modelsim post-routed simulation and onboard running on XUPV5-LX110T,are provided to demonstrate the effectiveness of the proposed method.
基金Supported by the National Natural Science Foundation of China(61271113)
文摘A binary tree representation is designed in this paper for optimization of wave digital filter(WDF)implementation.To achieve this,an equivalent WDF model of the original circuit is converted into abinary tree representation at first.This WDF binary tree can then be transformed to several topologies with the same implication,since the WDF adaptors have a symmetrical behavior on their ports.Because the WDF implementation is related to field programmable gate array(FPGA)resource usage and the cycle time of emulation,choosing aproper binary tree topology for WDF implementation can help balance the complexity and performance quality of an emulation system.Both WDF-FPGA emulation and HSpice simulation on the same circuit are tested.There is no significant difference between these two simulations.However,in terms of time consumption,the WDF-FPGA emulation has an advantage over the other.Our experiment also demonstrates that the optimized WDF-FPGA emulation has an acceptable accuracy and feasibility.
文摘With the rapid development of wireless systems,the demand for frequency resources has been increasing in recent years.Therefore,it is necessary to consider the high-quality communication method that efficiently utilizes finite frequency resources.In this paper,Single Sideband 16 Pulse Amplitude Modulation(SSB 16PAM)scheme for the uplink communication is proposed.It transmits data in only Lower Sideband(LSB)without extra Hilbert components.Under Additive White Gaussian Noise(AWGN)channel environment,Bit Error Rate(BER)performance of the proposed scheme is superior by 3 dB in terms of Carrier-to-Noise Ratio(CNR)to 256 Quadrature Amplitude Modulation(256QAM)scheme with the same frequency efficiency and the same Peak-to-Average Power Ratio(PAPR).Our proposed scheme employs the original frequency domain filter on the transmitter side to form an ideal spectrum.The configuration of its process is almost similar to Single Carrier-Frequency Division Multiple Access(SC-FDMA),moreover,half of the input data on the frequency domain is removed.The proposed frequency domain filter produces the SSB-modulated spectrum with a roll-off rate of zero without degrading the BER performance.
基金the National Key Research and Development Program of China(No.2016YFC060110403).
文摘Herein,a three-dimensional(3D)inversion method in the frequency domain based on a time–frequency transformation was developed to improve the efficiency of the 3D inversion of transient electromagnetic(TEM)data.The Fourier transform related to the electromagnetic response in the frequency and time domains becomes a sine or cosine transform under the excitation of downward-step current.We established a transformation matrix based on the digital fi ltering calculation for the sine transform,and then the frequency domain projection of the TEM data was determined from the linear transformation system using the smoothing constrained least squares inversion method,in which only the imaginary part was used to maintain the TEM data transformation equivalence in the bidirectional projection.Thus,the time-domain TEM inversion problem was indirectly and effectively solved in the frequency domain.In the 3D inversion of the transformed frequency-domain data,the limited-memory Broyden–Fletcher–Goldfarb–Shannoquasi–Newton(L-BFGS)method was used and modifi ed with a restart strategy to adjust the regularization parameter when the algorithm tended to a local minimum.Synthetic data tests showed that our domain transformation method can stably project the TEM data into the frequency domain with very high accuracy;furthe rmore,the 3D inversion of the transformed frequency-domain data is stable,can be used to recover the real resistivity model with an acceptable effi ciency.
文摘Some fast finite impulse response (FIR) filters use a large number of look-up tables (LUTs) to configure distributed random-access memories (RAMs) and save registers. The distributed RAMs store 2M precomputed sums of M permuted operands in order to simplify the accumulation, which lays similarity to the solution of Boolean satisfiability (SAT) problem. In this work, a high-speed fault-tolerant FIR digital filter on field programmable gate array (FPGA) is proposed for hardware implementation. A shift register and an RAM are used to arrange the data flow. Generally, an N-tap digital filter only requires N embedded multipliers on FPGA. The better performance is due to high-radix words and low-latency operations. A 32-tap 8-bit FIR digital filter enjoys a throughput of 9.17 MB/s, taking 109 ns to calculate one convolution. In addition, a fault-tolerant scheme by majority logic is used to correct real-time errors within digital filters.
文摘The digital filters with adjustable frequency-domain characteristics are called variable filters. Variable filters are useful in the applications where their characteristics are required to be changeable during the course of signal processing. Generally speaking, the variable frequency responses of a variable filters are the functions of a set of spectral parameters defining the desired frequencyUomain characteristics. In this paper, we first sample the given variable maghtode specifications and use them to construct a multi-dimensional (M - D) specification array, then propose an outer product expansion method for expanding it as the sum of the outer products of vectors. Using the outer product expansion, we can simplify the difficult problem of desighng a variable filter as the easy one that only needs constant 1 - D filter designs and 1 - D polynoIhal approximations. The method can obtain variable filters having arbitrary desired variable magnitude characteristics with a high design acctiracy.
基金supported by the National Plan-ning Committee(No.2002064).
文摘In order to eliminate the characteristic harmonics in high voltage direct current(HVDC)transmission systems and to simplify the analog controller structure,this paper proposes a new digital controller by adopting an approximate inverse system control strategy according to the frequency response characteristic of the hybrid power filter.The pro-posed digital controller is implemented with a TMS320C32 DSP,including a series of parallel digital band-pass filters,phase shifters and amplifiers.The results of both simulations based on PSCAD and experiments on a 30 kVA HVDC system prove that the proposed digital control system is sta-ble and efficient for eliminating the harmonics.
文摘The ongoing transformation of electrical power systems highlights the weaknesses of the protection schemes of traditional devices because they are designed and configured according to traditional characteristics of the system.Therefore,this work proposes a new methodology to study the fault-generated high frequency transient signals in transmission lines through multiresolution analysis.The high frequency components are determined by a new digital filtering technique based on mathematical morphology theory and a spectral energy index.Consequently,wide spectra of signals in the time–frequency domain are obtained.The performance of this method is verified on an electrical power system modeled in ATP-Draw,where simulation and test signals are developed for different locations,fault resistances,inception angles,high frequency noises,sampling frequencies,types of faults,and shapes of the structuring element.The results show the characteristics of the fault such as the traveling wave frequency,location,and starting time.
基金National Key R&D Program of China,No.2017YFC0403506Young Top-Notch Talent Support Program of National High-level Talents Special Support Plan and Strategic Consulting Projects of Chinese Academy of Engineering,No.2016-ZD-08-05-02。
文摘Baseflow is an important component of river or streamflow.It plays a vital role in water utilization and management.An improved Eckhardt recursive digital filter(IERDF)is proposed in this study.The key filter parameter and maximum baseflow index(BFImax)were estimated using the minimum smoothing method to improve baseflow estimation accuracy.The generally considered BFImax of 0.80,0.50 and 0.25 according to the drainage basin’s predominant geological characteristics often leads to significant errors in the regions that have complex subsurface and hydrologic conditions.The IERDF improved baseflow estimation accuracy by avoiding arbitrary parameter values.The proposed method was applied for baseflow separation in the upstream of Yitong River,a tributary of the Second Songhua River,and its performance was evaluated by comparing the results obtained using isotope-tracer data.The performance of IERDF was also compared with nine baseflow separation techniques belonging to filter,BFI and HYSEP methods.The IERDF was also applied for baseflow separation and calculation of rainfall infiltration recharge coefficient at different locations along the Second Songhua River’s mainstream for the period 2000–2016.The results showed that the minimum smoothing method significantly improved BFImax estimation accuracy.The baseflow process line obtained using IEDRF method was consistent with that obtained using isotope 18 O.The IERDF estimated baseflow also showed stability and reliability when applied in the mainstream of the Second Songhua River.The BFI alone in the river showed an increase from the upstream to the downstream.The proportion of baseflow to total flow showed a decrease with time.The intra-annual variability of BFI was different at different locations of the river due to varying climatic conditions and subsurface characteristics.The highest BFI was observed at the middle reaches of the river in summer due to a water surplus from power generation.The research provided valuable information on baseflow characteristics and runoff mode determination,which can be used for water resources assessment and optimization of economic activity distribution in the region.
文摘Runoff coefficient(C)values are tabulated and enshrined in hydrological engineering.These values are considered to be constant although they may not correspond to reality.In the same catchment,they may vary according to intensity,temporal and spatial distribution of precipitation events,humidity condi-tions,soil and land use.This study aimed to analyze extreme events of precipitation and their corre-sponding flows to obtain experimental runoff coefficients(C)and compare them with the tabulated values.The study was conducted in five experimental catchments in the state of S~ao Paulo,Brazil,with different land uses.The runoff coefficients(C)were obtained from the analysis of hydrograms and using a digital filter,which made it possible to separate the direct runoff from the total flow.We observed a different variation in runoff coefficient values between catchments compared to those obtained from the tables.The runoff coefficients had a high correlation with land use.In catchments with original vege-tation cover,such as Cerrado and forest,they varied little among the events analyzed,unlike the catchments where land use is diversified,with predominantly agricultural and urban occupation.
基金Project supported by the National High-Tech R&D Program(863)of China(No.2011AA010403)the National Natural Science Foundation of China(No.61474134)
文摘A wide-range tracking technique for clock and data recovery(CDR) circuit is presented. Compared to the traditional technique, a digital CDR controller with calibration is adopted to extend the tracking range. Because of the use of digital circuits in the design, CDR is not sensitive to process and power supply variations. To verify the technique, the whole CDR circuit is implemented using 65-nm CMOS technology. Measurements show that the tracking range of CDR is greater than ±6×10-3 at 5 Gb/s. The receiver has good jitter tolerance performance and achieves a bit error rate of <10–12. The re-timed and re-multiplexed serial data has a root-mean-square jitter of 6.7 ps.
