When building an adaptive noise cancellation system for wideband acoustic signals, one can meet some difficulties in practical implementation of such a system. The major problem is related to the necessity of using re...When building an adaptive noise cancellation system for wideband acoustic signals, one can meet some difficulties in practical implementation of such a system. The major problem is related to the necessity of using real-time signal generation and processing. In this paper the active noise control system which utilizes adaptation in frequency domain is considered. It is shown that the proposed algorithms simplify practical implementation of a noise cancellation system. The results of computer simulations and prototype experiments show the effectiveness of the proposed methods. .展开更多
A recent study demonstrated that in small-scale prepolarized surface nuclear magnetic resonance(SNMR-PP)measurements with a footprint of a few square meters,customized PP switch-off ramps can serve as an efficient exc...A recent study demonstrated that in small-scale prepolarized surface nuclear magnetic resonance(SNMR-PP)measurements with a footprint of a few square meters,customized PP switch-off ramps can serve as an efficient excitation mechanism,eliminating the requirement for a conventional oscillating excitation pulse.This approach enables the detection of short relaxation signals from the unsaturated soil zone and can,therefore,be used to directly provide soil moisture and pore geometry information.Because ultimately such small-scale SNMR-PP setups are intended for a mobile application,it is necessary to develop strategies that allow for speedy measurement progress and do not require noise cancellation protocols based on reference stations.Hence,we developed a new concentric figure-of-eight(cFOE)loop layout that combines the direction independence of a circular loop with the intrinsic noise cancellation properties of a classical FOE-loop.This approach significantly decreases the measurement time because suitable signal-to-noise ratios are reached much faster compared to a classical circular loop and will bring us one step further toward fast and non-invasive soil moisture mapping applications.展开更多
Active noise cancellation has become a prominent feature in contemporary in-ear personal audio devices.However,due to constraints related to component arrangement,power consumption,and manufacturing costs,most commerc...Active noise cancellation has become a prominent feature in contemporary in-ear personal audio devices.However,due to constraints related to component arrangement,power consumption,and manufacturing costs,most commercial products utilize fixed-type controller systems as the basis for their active noise control algorithms.These systems offer robust performance and a straightforward structure,which is achievable with cost-effective digital signal processors.Nonetheless,a major drawback of fixed-type controllers is their inability to adapt to changes in acoustic transfer paths,such as variations in earpiece fitting conditions.Therefore,adaptive-type active noise control systems that employ adaptive digital filters are considered as the alternative.To address the increasing system complexity,design concepts and implementation strategies are discussed with respect to actual hardware limitations.To illustrate these considerations,a case study showcasing the implementation of a filtered-x least mean square-based active noise control algorithm is presented.A commercial evaluation board accommodating a low-cost,fixed-point digital signal processor is used to simplify operation and provide programming access.The earbuds are obtained from a commercial product designed for noise cancellation.This study underscores the importance of addressing hardware constraints when implementing adaptive active noise cancellation,providing valuable insights for real-world applications.展开更多
Noise artifacts are one of the key obstacles in applying continuous monitoring and computer-assisted analysis of lung sounds. Traditional adaptive noise cancellation (ANC) methodologies work reasonably well when signa...Noise artifacts are one of the key obstacles in applying continuous monitoring and computer-assisted analysis of lung sounds. Traditional adaptive noise cancellation (ANC) methodologies work reasonably well when signal and noise are stationary and independent. Clinical lung sound auscultation encounters an acoustic environment in which breath sounds are not stationary and often correlate with noise. Consequendy, capability of ANC becomes significantly compromised. This paper introduces a new methodology for extracting authentic lung sounds from noise-corrupted measurements. Unlike traditional noise cancellation methods that rely on either frequency band separation or signal/noise independence to achieve noise reduction, this methodology combines the traditional noise canceling methods with the unique feature of time-split stages in breathing sounds. By employing a multi-sensor system, the method first employs a high-pass filter to eliminate the off-band noise, and then performs time-shared blind identification and noise cancellation with recursion from breathing cycle to cycle. Since no frequency separation or signal/noise independence is required, this method potentially has a robust and reliable capability of noise reduction, complementing the traditional methods.展开更多
Although a various of existing techniques are able to improve the performance of detection of the weak interesting sig- nal, how to adaptively and efficiently attenuate the intricate noises especially in the case of n...Although a various of existing techniques are able to improve the performance of detection of the weak interesting sig- nal, how to adaptively and efficiently attenuate the intricate noises especially in the case of no available reference noise signal is still the bottleneck to be overcome. According to the characteristics of sonar arrays, a multi-channel differencing method is presented to provide the prerequisite reference noise. However, the ingre- dient of obtained reference noise is too complicated to be used to effectively reduce the interference noise only using the clas- sical linear cancellation methods. Hence, a novel adaptive noise cancellation method based on the multi-kernel normalized least- mean-square algorithm consisting of weighted linear and Gaussian kernel functions is proposed, which allows to simultaneously con- sider the cancellation of linear and nonlinear components in the reference noise. The simulation results demonstrate that the out- put signal-to-noise ratio （SNR） of the novel multi-kernel adaptive filtering method outperforms the conventional linear normalized least-mean-square method and the mono-kernel normalized least- mean-square method using the realistic noise data measured in the lake experiment.展开更多
Daily, we experience the effects of audio noise, which contaminates the original information bearing signal with noise from its surrounding environment. This paper focuses on real-time hardware implementation of multi...Daily, we experience the effects of audio noise, which contaminates the original information bearing signal with noise from its surrounding environment. This paper focuses on real-time hardware implementation of multi-tap adaptive noise cancellation （ANC） system by using the least mean square （LMS） algorithm on TMS320C6713 to remove undesired noise from a received signal for various audio related applications. Three different experiments are carried out by considering different audio inputs to test the efficiency of the designed ANC system. The ＇C＇ code implementation of LMS algorithm is introduced and simulated in code composer studio （CCS）, then realized on the digital signal processor （DSP） C6713. The 300 Hz, 500 Hz, 800 Hz, 1 kHz and 3 kHz of tone signals and male speech signal are used as the reference inputs to trace the noise of signal until it is eliminated. The performance of ANC system is studied in terms of convergence speed, order of the filter and signal-to-noise ratio （SNR）. The experimentam results demonstrate that the designed system shows a consider- able improvement in SNR.展开更多
An inductorless Ultra-Wide Band （UWB） receiver frontend chip design used in wireless communications for the frequency band of 3.1 - 4.8 GHz is presented. This ho-nodyne receiver mainly consists of a diffexential Low...An inductorless Ultra-Wide Band （UWB） receiver frontend chip design used in wireless communications for the frequency band of 3.1 - 4.8 GHz is presented. This ho-nodyne receiver mainly consists of a diffexential Low Noise Amplifier （LNA） circuit followed by a down-converting mixer. The proposed LNA circuit with a noise canceling resistor is connected to the CMOS device＇s body to reduce the substrate thermal noise. Simulation and measuremnt results show that the chip can reduce the froat-end Noise Figure （NF） about 0.5dB and achieve the Conversion Gain （03） of 19.44-21.57 dB and double-sideband NF less than 7.8 dB. Also, the input third-order interoept point （IIP3） is - 11 dBm, and the input second-order intercept point （IIP2） is 49 dBm. Fabricated in TSMC 0.18 tan technology, this chip occupies only 0. 167 Iron2 and dissipates power 59.2 roW.展开更多
A novel nonlinear multi-input multi-output MIMO detection algorithm is proposed which is referred to as an ordered successive noise projection cancellation OSNPC algorithm. It is capable of improving the computation p...A novel nonlinear multi-input multi-output MIMO detection algorithm is proposed which is referred to as an ordered successive noise projection cancellation OSNPC algorithm. It is capable of improving the computation performance of the MIMO detector with the conventional ordered successive interference cancellation OSIC algorithm. In contrast to the OSIC in which the known interferences in the input signal vector are successively cancelled the OSNPC successively cancels the known noise projections from the decision statistic vector. Analysis indicates that the OSNPC is equivalent to the OSIC in error performance but it has significantly less complexity in computation.Furthermore when the OSNPC is applied to the MIMO detection with the preprocessing of dual lattice reduction DLR the computational complexity of the proposed OSNPC-based DLR-aided detector is further reduced due to the avoidance of the inverse of the reduced basis of the dual lattice in computation compared to that of the OSIC-based one. Simulation results validate the theoretical conclusions with regard to both the performance and complexity of the proposed MIMO detection scheme.展开更多
We theoretically investigate optomechanical force sensing via precooling and quantum noise cancellation in two coupled cavity optomechanical systems. We show that force sensing based on the reduction of noise can be u...We theoretically investigate optomechanical force sensing via precooling and quantum noise cancellation in two coupled cavity optomechanical systems. We show that force sensing based on the reduction of noise can be used to dramatically enhance the force sensing and that the precooling process can effectively improve the quantum noise cancellation. Specifically, we examine the effect of optomechanical cooling and noise reduction on the spectral density of the noise of the force measurement; these processes can significantly enhance the performance of optomechanical force sensing, and setting up the system in the resolved sideband regime can lead to an optimization of the cooling processes in a hybrid system. Such a scheme serves as a promising platform for quantum back-action-evading measurements of the motion and a framework for an optomechanical force sensor.展开更多
In this paper,we describe an optical path stabilization method in order to keep the phase of the clock laser fixed during the interrogation.The phase noise along the optical path of the clock laser is extracted from t...In this paper,we describe an optical path stabilization method in order to keep the phase of the clock laser fixed during the interrogation.The phase noise along the optical path of the clock laser is extracted from the heterodyne beat signals.Then an acousto-optic modulator(AOM)driven by direct digital synthesizer(DDS)receives a feedback signal to cancel the phase noise.The experimental results show that our system can effectively suppress additional phase noise.The fractional frequency instability is dropped to 1.76×10^-17/τ at 1 s,which is improved by two orders of magnitude than before.In the case of Rabi excitation with a pulse duration T=50 ms,frequency shift is 7.9 mHz due to the feedback system relock process.For phase noise from different frequency,the system has a good suppression effect on low frequency phase noise.展开更多
A wideband inductorless low noise amplifier for digital TV tuner applications is presented. The proposed LNA scheme uses a composite NMOS/PMOS cross-coupled transistor pair to provide partial cancellation of noise gen...A wideband inductorless low noise amplifier for digital TV tuner applications is presented. The proposed LNA scheme uses a composite NMOS/PMOS cross-coupled transistor pair to provide partial cancellation of noise generated by the input transistors. The chip is implemented in SMIC 0.18 #m CMOS technology. Measurement shows that the proposed LNA achieves 12.2-15.2 dB voltage gain from 300 to 900 MHz, the noise figure is below 3.1 dB and has a minimum value of 2.3 dB, and the best input-referred 1-dB compression point （IPldB） is - 17 dBm at 900 MHz. The core consumes 7 mA current with a supply voltage of 1.8 V and occupies an area of 0.5 x 0.35 mm2.展开更多
This paper presents a broadband Gilbert low noise mixer implemented with noise cancellation technique operating between 10 MHz and 0.9 GHz.The Gilbert mixer is known for its perfect port isolation and bad noise perfor...This paper presents a broadband Gilbert low noise mixer implemented with noise cancellation technique operating between 10 MHz and 0.9 GHz.The Gilbert mixer is known for its perfect port isolation and bad noise performance.The noise cancellation technique of LNA can be applied here to have a better NF.The chip is implemented in SMIC 0.18μm CMOS technology.Measurement shows that the proposed low noise mixer has a 13.7-19.5 dB voltage gain from 10 MHz to 0.9 GHz,an average noise figure of 5 dB and a minimum value of 4.3 dB.The core area is 0.6 x 0.45 mm^2.展开更多
We demonstrate coherent optical frequency dissemination over a distance of 972 km by cascading two spans where the phase noise is passively compensated for.Instead of employing a phase discriminator and a phase lockin...We demonstrate coherent optical frequency dissemination over a distance of 972 km by cascading two spans where the phase noise is passively compensated for.Instead of employing a phase discriminator and a phase locking loop in the conventional active phase control scheme,the passive phase noise cancellation is realized by feeding double-trip beat-note frequency to the driver of the acoustic optical modulator at the local site.This passive scheme exhibits fine robustness and reliability,making it suitable for long-distance and noisy fiber links.An optical regeneration station is used in the link for signal amplification and cascaded transmission.The phase noise cancellation and transfer instability of the 972-km link is investigated,and transfer instability of 1.1×10^(-19)at 10^(4)s is achieved.This work provides a promising method for realizing optical frequency distribution over thousands of kilometers by using fiber links.展开更多
With the purpose of reducing the influence of background noise on the call quality of mobile phones, background noise suppression circuit is designed based on the principle of self-adaptive noise cancellation. Because...With the purpose of reducing the influence of background noise on the call quality of mobile phones, background noise suppression circuit is designed based on the principle of self-adaptive noise cancellation. Because this method is not involved in the nature of the noise itself, it can be used both for stationary noise cancellation and quasi-stationary noise cancellation. The working principle and circuit design of the system are introduced in detail. Simulated experiment was conducted in the lab, and its experimental results were analyzed. The experimental results show that the circuit works well with low cost, and has a broad prospect of application and popularization.展开更多
Headphones with an integrated active noise cancellation system have been increasingly introduced to the consumer market in recent years. When exposing the human ear to active noise sources in this striking distance, t...Headphones with an integrated active noise cancellation system have been increasingly introduced to the consumer market in recent years. When exposing the human ear to active noise sources in this striking distance, the ensuring of a safe sound pressure level is vital. In feedback systems, this is coupled with the stability of the closed control loop; stable controller design is thus essential. However, changes in the control path during run-time can cause the stable control system to become unstable, resulting in an overdrive of the speakers in the headphones. This paper proposes a method, which enables the real-time analysis of the current system state and if necessary stabilizes the closed loop while maintaining the active noise reduction. This is achieved by estimating and evaluating the open loop behavior with an adaptive filter and subsequently limiting the controller gain in respect to the stability margin.展开更多
With the development of the times,people’s requirements for communication technology are becoming higher and higher.4G communication technology has been unable to meet development needs,and 5G communication technolog...With the development of the times,people’s requirements for communication technology are becoming higher and higher.4G communication technology has been unable to meet development needs,and 5G communication technology has emerged as the times require.This article proposes the design of a low-noise amplifier(LNA)that will be used in the 5G band of China Mobile Communications.A low noise amplifier for mobile 5G communication is designed based on Taiwan Semiconductor Manufacturing Company(TSMC)0.13μm Radio Frequency(RF)Complementary Metal Oxide Semiconductor(CMOS)process.The LNA employs self-cascode devices in current-reuse configuration to enable lower supply voltage operation without compromising the gain.This design uses an active feedback amplifier to achieve input impedance matching,avoiding the introduction of resistive negative feedback to reduce gain.A common source(CS)amplifier is used as the input of the low noise amplifier.In order to achieve the low power consumption of LNA,current reuse technology is used to reduce power consumption.Noise cancellation techniques are used to eliminate noise.The simulation results in a maximum power gain of 22.783,the reverse isolation(S12)less than-48.092 dB,noise figure(NF)less than 1.878 dB,minimum noise figure(NFmin)=1.203 dB,input return loss(S11)and output return loss(S22)are both less than-14.933 dB in the frequency range of 2515-4900 MHz.The proposed Ultra-wideband(UWB)LNA consumed 1.424 mW without buffer from a 1.2 V power supply.展开更多
The adaptive algorithm used for echo cancellation(EC) system needs to provide 1) low misadjustment and 2) high convergence rate. The affine projection algorithm(APA) is a better alternative than normalized least mean ...The adaptive algorithm used for echo cancellation(EC) system needs to provide 1) low misadjustment and 2) high convergence rate. The affine projection algorithm(APA) is a better alternative than normalized least mean square(NLMS) algorithm in EC applications where the input signal is highly correlated. Since the APA with a constant step-size has to make compromise between the performance criteria 1) and 2), a variable step-size APA(VSS-APA) provides a more reliable solution. A nonparametric VSS-APA(NPVSS-APA) is proposed by recovering the background noise within the error signal instead of cancelling the a posteriori errors. The most problematic term of its variable step-size formula is the value of background noise power(BNP). The power difference between the desired signal and output signal, which equals the power of error signal statistically, has been considered the BNP estimate in a rough manner. Considering that the error signal consists of background noise and misalignment noise, a precise BNP estimate is achieved by multiplying the rough estimate with a corrective factor. After the analysis on the power ratio of misalignment noise to background noise of APA, the corrective factor is formulated depending on the projection order and the latest value of variable step-size. The new algorithm which does not require any a priori knowledge of EC environment has the advantage of easier controllability in practical application. The simulation results in the EC context indicate the accuracy of the proposed BNP estimate and the more effective behavior of the proposed algorithm compared with other versions of APA class.展开更多
The least mean square error difference （LMS-ED） minimum criterion for an adaptive chaotic noise canceller is proposed in this paper. Different from traditional least mean square error minimum criterion in which the ...The least mean square error difference （LMS-ED） minimum criterion for an adaptive chaotic noise canceller is proposed in this paper. Different from traditional least mean square error minimum criterion in which the error is uncorrelated with the input vector, the proposed LMS-ED minimum criterion tries to minimize the correlation between the error difference and input vector difference. The novel adaptive LMS-ED algorithm is then derived to update the weights of adaptive noise canceller. A comparison between cancelling performances of adaptive least mean square （LMS）, normalized LMS （NLMS） and proposed LMS-ED algorithms is simulated by using three kinds of chaotic noises. The simulation results clearly show that the proposed algorithm outperforms the LMS and NLMS algorithms in achieving small values of steady-state excess mean square error. Moreover, the computational complexity of the proposed LMS-ED algorithm is the same as that of the standard LMS algorithms.展开更多
AIM:To explore the more accurate lung sounds auscultation technology in high battlefield noise environment.METHODS: In this study, we restrain high background noise using a new method-adaptive noise canceling based on...AIM:To explore the more accurate lung sounds auscultation technology in high battlefield noise environment.METHODS: In this study, we restrain high background noise using a new method-adaptive noise canceling based on independent component analysis (ANC-ICA), the method, by incorporating both second-order and higher-order statistics can remove noise components of the primary input signal based on statistical independence.RESULTS:The algorithm retained the local feature of lung sounds while eliminating high background noise, and performed more effectively than the conventional LMS algorithm.CONCLUSION:This method can cancel high battlefield noise of lung sounds effectively thus can help diagnose lung disease more accurately.展开更多
The successive approximation register(SAR)is one of the most energy-efficient analog-to-digital converter(ADC)architecture for medium-resolution applications.However,its high energy efficiency quickly diminishes when ...The successive approximation register(SAR)is one of the most energy-efficient analog-to-digital converter(ADC)architecture for medium-resolution applications.However,its high energy efficiency quickly diminishes when the target resolution increases.This is because a SAR ADC suffers from several major error source,including the sampling kT/C noise,the comparator noise,and the DAC mismatch.These errors are increasing hard to address in high-resolution SAR ADCs.This paper reviews recent advances on error suppression techniques for SAR ADCs,including the sampling kT/C noise reduction,the noise-shaping(NS)SAR,and the mismatch error shaping(MES).These techniques aim to boost the resolution of SAR ADCs while maintaining their superior energy efficiency.展开更多
文摘When building an adaptive noise cancellation system for wideband acoustic signals, one can meet some difficulties in practical implementation of such a system. The major problem is related to the necessity of using real-time signal generation and processing. In this paper the active noise control system which utilizes adaptation in frequency domain is considered. It is shown that the proposed algorithms simplify practical implementation of a noise cancellation system. The results of computer simulations and prototype experiments show the effectiveness of the proposed methods. .
基金supported by the German Research Foundation(Deutsche Forschungsgemeinschaft-DFG)under grant MU 3318/4-1.
文摘A recent study demonstrated that in small-scale prepolarized surface nuclear magnetic resonance(SNMR-PP)measurements with a footprint of a few square meters,customized PP switch-off ramps can serve as an efficient excitation mechanism,eliminating the requirement for a conventional oscillating excitation pulse.This approach enables the detection of short relaxation signals from the unsaturated soil zone and can,therefore,be used to directly provide soil moisture and pore geometry information.Because ultimately such small-scale SNMR-PP setups are intended for a mobile application,it is necessary to develop strategies that allow for speedy measurement progress and do not require noise cancellation protocols based on reference stations.Hence,we developed a new concentric figure-of-eight(cFOE)loop layout that combines the direction independence of a circular loop with the intrinsic noise cancellation properties of a classical FOE-loop.This approach significantly decreases the measurement time because suitable signal-to-noise ratios are reached much faster compared to a classical circular loop and will bring us one step further toward fast and non-invasive soil moisture mapping applications.
文摘Active noise cancellation has become a prominent feature in contemporary in-ear personal audio devices.However,due to constraints related to component arrangement,power consumption,and manufacturing costs,most commercial products utilize fixed-type controller systems as the basis for their active noise control algorithms.These systems offer robust performance and a straightforward structure,which is achievable with cost-effective digital signal processors.Nonetheless,a major drawback of fixed-type controllers is their inability to adapt to changes in acoustic transfer paths,such as variations in earpiece fitting conditions.Therefore,adaptive-type active noise control systems that employ adaptive digital filters are considered as the alternative.To address the increasing system complexity,design concepts and implementation strategies are discussed with respect to actual hardware limitations.To illustrate these considerations,a case study showcasing the implementation of a filtered-x least mean square-based active noise control algorithm is presented.A commercial evaluation board accommodating a low-cost,fixed-point digital signal processor is used to simplify operation and provide programming access.The earbuds are obtained from a commercial product designed for noise cancellation.This study underscores the importance of addressing hardware constraints when implementing adaptive active noise cancellation,providing valuable insights for real-world applications.
基金Hong Wang's research was supported in part by the Anesthesiology Department at Wayne State University and in part by Wayne State University Research Enhancement ProgramLeyi Wang" s research was supported in part by the National Science Foundation ( No.
文摘Noise artifacts are one of the key obstacles in applying continuous monitoring and computer-assisted analysis of lung sounds. Traditional adaptive noise cancellation (ANC) methodologies work reasonably well when signal and noise are stationary and independent. Clinical lung sound auscultation encounters an acoustic environment in which breath sounds are not stationary and often correlate with noise. Consequendy, capability of ANC becomes significantly compromised. This paper introduces a new methodology for extracting authentic lung sounds from noise-corrupted measurements. Unlike traditional noise cancellation methods that rely on either frequency band separation or signal/noise independence to achieve noise reduction, this methodology combines the traditional noise canceling methods with the unique feature of time-split stages in breathing sounds. By employing a multi-sensor system, the method first employs a high-pass filter to eliminate the off-band noise, and then performs time-shared blind identification and noise cancellation with recursion from breathing cycle to cycle. Since no frequency separation or signal/noise independence is required, this method potentially has a robust and reliable capability of noise reduction, complementing the traditional methods.
基金supported by the National Natural Science Foundation of China(6100115361271415)+2 种基金the Opening Research Foundation of State Key Laboratory of Underwater Information Processing and Control(9140C231002130C23085)the Fundamental Research Funds for the Central Universities(3102014JCQ010103102014ZD0041)
文摘Although a various of existing techniques are able to improve the performance of detection of the weak interesting sig- nal, how to adaptively and efficiently attenuate the intricate noises especially in the case of no available reference noise signal is still the bottleneck to be overcome. According to the characteristics of sonar arrays, a multi-channel differencing method is presented to provide the prerequisite reference noise. However, the ingre- dient of obtained reference noise is too complicated to be used to effectively reduce the interference noise only using the clas- sical linear cancellation methods. Hence, a novel adaptive noise cancellation method based on the multi-kernel normalized least- mean-square algorithm consisting of weighted linear and Gaussian kernel functions is proposed, which allows to simultaneously con- sider the cancellation of linear and nonlinear components in the reference noise. The simulation results demonstrate that the out- put signal-to-noise ratio （SNR） of the novel multi-kernel adaptive filtering method outperforms the conventional linear normalized least-mean-square method and the mono-kernel normalized least- mean-square method using the realistic noise data measured in the lake experiment.
文摘Daily, we experience the effects of audio noise, which contaminates the original information bearing signal with noise from its surrounding environment. This paper focuses on real-time hardware implementation of multi-tap adaptive noise cancellation （ANC） system by using the least mean square （LMS） algorithm on TMS320C6713 to remove undesired noise from a received signal for various audio related applications. Three different experiments are carried out by considering different audio inputs to test the efficiency of the designed ANC system. The ＇C＇ code implementation of LMS algorithm is introduced and simulated in code composer studio （CCS）, then realized on the digital signal processor （DSP） C6713. The 300 Hz, 500 Hz, 800 Hz, 1 kHz and 3 kHz of tone signals and male speech signal are used as the reference inputs to trace the noise of signal until it is eliminated. The performance of ANC system is studied in terms of convergence speed, order of the filter and signal-to-noise ratio （SNR）. The experimentam results demonstrate that the designed system shows a consider- able improvement in SNR.
文摘An inductorless Ultra-Wide Band （UWB） receiver frontend chip design used in wireless communications for the frequency band of 3.1 - 4.8 GHz is presented. This ho-nodyne receiver mainly consists of a diffexential Low Noise Amplifier （LNA） circuit followed by a down-converting mixer. The proposed LNA circuit with a noise canceling resistor is connected to the CMOS device＇s body to reduce the substrate thermal noise. Simulation and measuremnt results show that the chip can reduce the froat-end Noise Figure （NF） about 0.5dB and achieve the Conversion Gain （03） of 19.44-21.57 dB and double-sideband NF less than 7.8 dB. Also, the input third-order interoept point （IIP3） is - 11 dBm, and the input second-order intercept point （IIP2） is 49 dBm. Fabricated in TSMC 0.18 tan technology, this chip occupies only 0. 167 Iron2 and dissipates power 59.2 roW.
基金The National Science and Technology Major Project(No.2012ZX03004005-003)the National Natural Science Foundation of China(No.61171081,61201175)the Innovation Technology Fund of Jiangsu Province(No.BC2012006)
文摘A novel nonlinear multi-input multi-output MIMO detection algorithm is proposed which is referred to as an ordered successive noise projection cancellation OSNPC algorithm. It is capable of improving the computation performance of the MIMO detector with the conventional ordered successive interference cancellation OSIC algorithm. In contrast to the OSIC in which the known interferences in the input signal vector are successively cancelled the OSNPC successively cancels the known noise projections from the decision statistic vector. Analysis indicates that the OSNPC is equivalent to the OSIC in error performance but it has significantly less complexity in computation.Furthermore when the OSNPC is applied to the MIMO detection with the preprocessing of dual lattice reduction DLR the computational complexity of the proposed OSNPC-based DLR-aided detector is further reduced due to the avoidance of the inverse of the reduced basis of the dual lattice in computation compared to that of the OSIC-based one. Simulation results validate the theoretical conclusions with regard to both the performance and complexity of the proposed MIMO detection scheme.
基金supported by the Arba Minch University Ethiopia,and the National Natural Science Foundation of China(Grant Nos.11574041,and 11475037)
文摘We theoretically investigate optomechanical force sensing via precooling and quantum noise cancellation in two coupled cavity optomechanical systems. We show that force sensing based on the reduction of noise can be used to dramatically enhance the force sensing and that the precooling process can effectively improve the quantum noise cancellation. Specifically, we examine the effect of optomechanical cooling and noise reduction on the spectral density of the noise of the force measurement; these processes can significantly enhance the performance of optomechanical force sensing, and setting up the system in the resolved sideband regime can lead to an optimization of the cooling processes in a hybrid system. Such a scheme serves as a promising platform for quantum back-action-evading measurements of the motion and a framework for an optomechanical force sensor.
基金Supported by the National Natural Science Foundation of China(11574352)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB21030100)。
文摘In this paper,we describe an optical path stabilization method in order to keep the phase of the clock laser fixed during the interrogation.The phase noise along the optical path of the clock laser is extracted from the heterodyne beat signals.Then an acousto-optic modulator(AOM)driven by direct digital synthesizer(DDS)receives a feedback signal to cancel the phase noise.The experimental results show that our system can effectively suppress additional phase noise.The fractional frequency instability is dropped to 1.76×10^-17/τ at 1 s,which is improved by two orders of magnitude than before.In the case of Rabi excitation with a pulse duration T=50 ms,frequency shift is 7.9 mHz due to the feedback system relock process.For phase noise from different frequency,the system has a good suppression effect on low frequency phase noise.
基金supported by the National Science and Technology Major Project,China(No.2011ZX03004-002-01)
文摘A wideband inductorless low noise amplifier for digital TV tuner applications is presented. The proposed LNA scheme uses a composite NMOS/PMOS cross-coupled transistor pair to provide partial cancellation of noise generated by the input transistors. The chip is implemented in SMIC 0.18 #m CMOS technology. Measurement shows that the proposed LNA achieves 12.2-15.2 dB voltage gain from 300 to 900 MHz, the noise figure is below 3.1 dB and has a minimum value of 2.3 dB, and the best input-referred 1-dB compression point （IPldB） is - 17 dBm at 900 MHz. The core consumes 7 mA current with a supply voltage of 1.8 V and occupies an area of 0.5 x 0.35 mm2.
基金supported by the National Science and Technology Major Project,China(No.2008ZX03006-009)
文摘This paper presents a broadband Gilbert low noise mixer implemented with noise cancellation technique operating between 10 MHz and 0.9 GHz.The Gilbert mixer is known for its perfect port isolation and bad noise performance.The noise cancellation technique of LNA can be applied here to have a better NF.The chip is implemented in SMIC 0.18μm CMOS technology.Measurement shows that the proposed low noise mixer has a 13.7-19.5 dB voltage gain from 10 MHz to 0.9 GHz,an average noise figure of 5 dB and a minimum value of 4.3 dB.The core area is 0.6 x 0.45 mm^2.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12103059,12033007,12303077,and 12303076)the Fund from the Xi’an Science and Technology Bureau,China(Grant No.E019XK1S04)the Fund from the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.1188000XGJ).
文摘We demonstrate coherent optical frequency dissemination over a distance of 972 km by cascading two spans where the phase noise is passively compensated for.Instead of employing a phase discriminator and a phase locking loop in the conventional active phase control scheme,the passive phase noise cancellation is realized by feeding double-trip beat-note frequency to the driver of the acoustic optical modulator at the local site.This passive scheme exhibits fine robustness and reliability,making it suitable for long-distance and noisy fiber links.An optical regeneration station is used in the link for signal amplification and cascaded transmission.The phase noise cancellation and transfer instability of the 972-km link is investigated,and transfer instability of 1.1×10^(-19)at 10^(4)s is achieved.This work provides a promising method for realizing optical frequency distribution over thousands of kilometers by using fiber links.
文摘With the purpose of reducing the influence of background noise on the call quality of mobile phones, background noise suppression circuit is designed based on the principle of self-adaptive noise cancellation. Because this method is not involved in the nature of the noise itself, it can be used both for stationary noise cancellation and quasi-stationary noise cancellation. The working principle and circuit design of the system are introduced in detail. Simulated experiment was conducted in the lab, and its experimental results were analyzed. The experimental results show that the circuit works well with low cost, and has a broad prospect of application and popularization.
文摘Headphones with an integrated active noise cancellation system have been increasingly introduced to the consumer market in recent years. When exposing the human ear to active noise sources in this striking distance, the ensuring of a safe sound pressure level is vital. In feedback systems, this is coupled with the stability of the closed control loop; stable controller design is thus essential. However, changes in the control path during run-time can cause the stable control system to become unstable, resulting in an overdrive of the speakers in the headphones. This paper proposes a method, which enables the real-time analysis of the current system state and if necessary stabilizes the closed loop while maintaining the active noise reduction. This is achieved by estimating and evaluating the open loop behavior with an adaptive filter and subsequently limiting the controller gain in respect to the stability margin.
基金This work was financially supported by the National Natural Science Foundation(No.61806088)Jiangsu Province Industry-University-Research Cooperation Project(No.BY2018191)+1 种基金Natural Science Fund of Changzhou(CE20175026)Qing Lan Project of Jiangsu Province.
文摘With the development of the times,people’s requirements for communication technology are becoming higher and higher.4G communication technology has been unable to meet development needs,and 5G communication technology has emerged as the times require.This article proposes the design of a low-noise amplifier(LNA)that will be used in the 5G band of China Mobile Communications.A low noise amplifier for mobile 5G communication is designed based on Taiwan Semiconductor Manufacturing Company(TSMC)0.13μm Radio Frequency(RF)Complementary Metal Oxide Semiconductor(CMOS)process.The LNA employs self-cascode devices in current-reuse configuration to enable lower supply voltage operation without compromising the gain.This design uses an active feedback amplifier to achieve input impedance matching,avoiding the introduction of resistive negative feedback to reduce gain.A common source(CS)amplifier is used as the input of the low noise amplifier.In order to achieve the low power consumption of LNA,current reuse technology is used to reduce power consumption.Noise cancellation techniques are used to eliminate noise.The simulation results in a maximum power gain of 22.783,the reverse isolation(S12)less than-48.092 dB,noise figure(NF)less than 1.878 dB,minimum noise figure(NFmin)=1.203 dB,input return loss(S11)and output return loss(S22)are both less than-14.933 dB in the frequency range of 2515-4900 MHz.The proposed Ultra-wideband(UWB)LNA consumed 1.424 mW without buffer from a 1.2 V power supply.
文摘The adaptive algorithm used for echo cancellation(EC) system needs to provide 1) low misadjustment and 2) high convergence rate. The affine projection algorithm(APA) is a better alternative than normalized least mean square(NLMS) algorithm in EC applications where the input signal is highly correlated. Since the APA with a constant step-size has to make compromise between the performance criteria 1) and 2), a variable step-size APA(VSS-APA) provides a more reliable solution. A nonparametric VSS-APA(NPVSS-APA) is proposed by recovering the background noise within the error signal instead of cancelling the a posteriori errors. The most problematic term of its variable step-size formula is the value of background noise power(BNP). The power difference between the desired signal and output signal, which equals the power of error signal statistically, has been considered the BNP estimate in a rough manner. Considering that the error signal consists of background noise and misalignment noise, a precise BNP estimate is achieved by multiplying the rough estimate with a corrective factor. After the analysis on the power ratio of misalignment noise to background noise of APA, the corrective factor is formulated depending on the projection order and the latest value of variable step-size. The new algorithm which does not require any a priori knowledge of EC environment has the advantage of easier controllability in practical application. The simulation results in the EC context indicate the accuracy of the proposed BNP estimate and the more effective behavior of the proposed algorithm compared with other versions of APA class.
基金Supported by the National Natural Science Foundation of China （grant No 60572027）, the Program for New Century Excellent Talents in University of China （Grant No NCET-05- 0794）, and the National Key Lab. of Anti-jamming Conununication Foundation of University of Electronic Science and Technology of China （Grant Nos 51434110104QT2201 and 51435080104QT2201）.
文摘The least mean square error difference （LMS-ED） minimum criterion for an adaptive chaotic noise canceller is proposed in this paper. Different from traditional least mean square error minimum criterion in which the error is uncorrelated with the input vector, the proposed LMS-ED minimum criterion tries to minimize the correlation between the error difference and input vector difference. The novel adaptive LMS-ED algorithm is then derived to update the weights of adaptive noise canceller. A comparison between cancelling performances of adaptive least mean square （LMS）, normalized LMS （NLMS） and proposed LMS-ED algorithms is simulated by using three kinds of chaotic noises. The simulation results clearly show that the proposed algorithm outperforms the LMS and NLMS algorithms in achieving small values of steady-state excess mean square error. Moreover, the computational complexity of the proposed LMS-ED algorithm is the same as that of the standard LMS algorithms.
基金Supported by Obligatory Budget of Chine PLA in the "tenth-five years"(OIL077)
文摘AIM:To explore the more accurate lung sounds auscultation technology in high battlefield noise environment.METHODS: In this study, we restrain high background noise using a new method-adaptive noise canceling based on independent component analysis (ANC-ICA), the method, by incorporating both second-order and higher-order statistics can remove noise components of the primary input signal based on statistical independence.RESULTS:The algorithm retained the local feature of lung sounds while eliminating high background noise, and performed more effectively than the conventional LMS algorithm.CONCLUSION:This method can cancel high battlefield noise of lung sounds effectively thus can help diagnose lung disease more accurately.
基金supported by National Natural Science Foundation of China(No.61904094,No.61934009)China Postdoctoral Science Foundation(No.2020M670329)Beijing Innovation Center for Future Chips(ICFC).
文摘The successive approximation register(SAR)is one of the most energy-efficient analog-to-digital converter(ADC)architecture for medium-resolution applications.However,its high energy efficiency quickly diminishes when the target resolution increases.This is because a SAR ADC suffers from several major error source,including the sampling kT/C noise,the comparator noise,and the DAC mismatch.These errors are increasing hard to address in high-resolution SAR ADCs.This paper reviews recent advances on error suppression techniques for SAR ADCs,including the sampling kT/C noise reduction,the noise-shaping(NS)SAR,and the mismatch error shaping(MES).These techniques aim to boost the resolution of SAR ADCs while maintaining their superior energy efficiency.
