The approach of estimating the number of signals based on information theoretic criteria has good performance in the assumption of white noise, but it always leads to false estimation of the coherent sources in colore...The approach of estimating the number of signals based on information theoretic criteria has good performance in the assumption of white noise, but it always leads to false estimation of the coherent sources in colored noise. An approach combining the combined information theoretic criteria and eigen- value correction, is presented to determine number of signals. The method uses maximum likelihood （ML） and information theoretic criteria to estimate coherent signals alternately, then eliminate the inequality of the eigenvalues caused by colored noise by correcting the noise eigenvalues. The computer simulation results prove the effective performance of the method.展开更多
A single-mode laser noise model driven by quadratic colored pump noise and biased amplitude modulationsignal is proposed.The analytic expression of signal-to-noise ratio is calculated by using a new linearized procedu...A single-mode laser noise model driven by quadratic colored pump noise and biased amplitude modulationsignal is proposed.The analytic expression of signal-to-noise ratio is calculated by using a new linearized procedure.Itis found that there are three different typies of stochastic resonance in the model:the conventional form of stochasticresonance,the stochastic resonance in the broad sense,and the bona fide SR.展开更多
This paper investigates the signal-to-noise ratio(SNR)driven by colored noise and weak input signals.Based on the Cauchy-Schwarz and Rayleigh quotients inequalities,an analytical expression of SNR is developed,and its...This paper investigates the signal-to-noise ratio(SNR)driven by colored noise and weak input signals.Based on the Cauchy-Schwarz and Rayleigh quotients inequalities,an analytical expression of SNR is developed,and its upper band is closely related to the Fisher information of noise.For mimicking the colored noise,we adopt the first-order moving-average model and propose the optimal input signal waveform.The stochastic resonance effect in threshold systems is demonstrated for the Gaussian mixture colored noise.The obtained results will be interesting in the case of improving the nonlinear filter performance by adding noise to the weak signal corrupted by the colored noise.展开更多
目的:分析彩色多普勒超声在双波长激光治疗婴幼儿血管瘤的应用价值。方法:回顾性分析2021年3月至2023年3月收治的血管瘤患者临床资料,所有患者在行Cynergy双波长激光治疗前均接受彩色多普勒超声检查,根据不同的血流信号和皮损深度,观察...目的:分析彩色多普勒超声在双波长激光治疗婴幼儿血管瘤的应用价值。方法:回顾性分析2021年3月至2023年3月收治的血管瘤患者临床资料,所有患者在行Cynergy双波长激光治疗前均接受彩色多普勒超声检查,根据不同的血流信号和皮损深度,观察治疗效果及并发症发生情况。结果:198例血管瘤患儿纳入分析,共计212处皮损,其中根据血流信号分为无血流信号73例(34.3%)、稀少血流信号76例(35.8%)、中等血流信号63例(29.9%),有效率为100%,96.1%,85.7%,三组比较差异有统计学意义(P<0.05);根据皮损深度分为<1.2 mm 69例(32.5%),1.2~3.0 mm 88例(41.5%),>3 mm 55例(26.0%),有效率为100%,94.3%,83.6%,三组比较差异有统计学意义(P<0.05);在所有纳入的患者中,有21.7%的患儿出现不良反应。结论:彩色多普勒超声在双波长激光治疗婴幼儿血管瘤中具有重要的应用价值,可以实时监测治疗过程,并帮助临床医师预估疗效。展开更多
In this paper, we propose extraction of signals correlated with noise in which they are buried. Proposed extraction method uses no a-priori information on the buried signal and works independently of the nature of noi...In this paper, we propose extraction of signals correlated with noise in which they are buried. Proposed extraction method uses no a-priori information on the buried signal and works independently of the nature of noise, correlated or not with the signal, colored or white, Gaussian or not, and locations of its spectral extent. Extraction of buried correlated signals is achieved without averaging in the time or frequency domain.展开更多
This letter demonstrates the structure of the passive radar using TV signals. Because the TV signal is a kind of pseudoperiodic signal, the matched filtering of color TV signals would yield high sidelobes which cause ...This letter demonstrates the structure of the passive radar using TV signals. Because the TV signal is a kind of pseudoperiodic signal, the matched filtering of color TV signals would yield high sidelobes which cause the range ambiguity. To overcome this problem, the mismatched filter is proposed to suppress the correlation sidelobes of matched filtering of TV signals. By utilizing the iteration process, this method could achieve the required peak sidelobe level. The impacts of the noise and target movement on mismatched filtering are also analysed. Simulation results are included to demonstrate the effectiveness of the proposed technique.展开更多
The cross-spectral estimation methods are efficient in estimating the parameters of sinusoidal signals embedded in colored noise. But up to now, only FPT and cross-periodogram methods are used in this field, the moder...The cross-spectral estimation methods are efficient in estimating the parameters of sinusoidal signals embedded in colored noise. But up to now, only FPT and cross-periodogram methods are used in this field, the modern auto-spectral estimation method is introduced into cross-spectral estimation in this paper, meanwhile the cross-correlation based Yule-Walker equation is proposed theoretically and the moment and singular-value decomposition (SVD)) algorithms for cross-spectral estimation have been developed. Finally, a numerical example is given for comparing the presented methods with the well-known Cadzow’s SVD method.展开更多
The phenomenon of stochastic resonance (SR) in a bistable nonlinear system is studied when the system is driven by the asymmetric potential and additive Gaussian colored noise. Using the unified colored noise approxim...The phenomenon of stochastic resonance (SR) in a bistable nonlinear system is studied when the system is driven by the asymmetric potential and additive Gaussian colored noise. Using the unified colored noise approximation method, the additive Gaussian colored noise can be simplified to additive Gaussian white noise. The signal-to-noise ratio (SNR) is calculated according to the generalized two-state theory (shown in [H.S. Wio and S. Bouzat, Brazilian J.Phys. 29 (1999) 136]). We find that the SNR increases with the proximity of a to zero. In addition, the correlation time τ between the additive Gaussian colored noise is also an ingredient to improve SR. The shorter the correlation time τ between the Gaussian additive colored noise is, the higher of the peak value of SNR.展开更多
In this paper, we propose extraction of signals buried in non-ergodic processes. It is shown that the proposed method extracts signals defined in a non-ergodic framework without averaging or smoothing in the direct ti...In this paper, we propose extraction of signals buried in non-ergodic processes. It is shown that the proposed method extracts signals defined in a non-ergodic framework without averaging or smoothing in the direct time or frequency domain. Extraction is achieved independently of the nature of noise, correlated or not with the signal, colored or white, Gaussian or not, and locations of its spectral extent. Performances of the pro-posed extraction method and comparative results with other methods are demonstrated via experimental Doppler velocimetry measurements.展开更多
针对色噪声下基于差分去噪的宽带相干信号波达方向(direction of arrival,DOA)估计方法对相干信源数有限制的问题,提出一种基于噪声圆形特性去噪和Toeplitz矩阵重构的估计算法。首先,对接收到的信号求取协方差矩阵,利用噪声的圆形特性...针对色噪声下基于差分去噪的宽带相干信号波达方向(direction of arrival,DOA)估计方法对相干信源数有限制的问题,提出一种基于噪声圆形特性去噪和Toeplitz矩阵重构的估计算法。首先,对接收到的信号求取协方差矩阵,利用噪声的圆形特性消除噪声。为达到对协方差矩阵进行Toeplitz矩阵重构的要求,通过协方差矩阵相乘来构造新的数据协方差矩阵。然后,通过Toeplitz矩阵重构来解相干。最后,利用旋转子空间算法准则构造聚焦矩阵,使用传播算子算法实现DOA估计。理论分析及仿真实验验证了该算法的有效性,该算法对相干信源数的奇偶没有限制,同时该算法也适用于高斯白噪声下宽带相干信号DOA估计的场景。展开更多
文摘The approach of estimating the number of signals based on information theoretic criteria has good performance in the assumption of white noise, but it always leads to false estimation of the coherent sources in colored noise. An approach combining the combined information theoretic criteria and eigen- value correction, is presented to determine number of signals. The method uses maximum likelihood （ML） and information theoretic criteria to estimate coherent signals alternately, then eliminate the inequality of the eigenvalues caused by colored noise by correcting the noise eigenvalues. The computer simulation results prove the effective performance of the method.
基金Supported by National Natural Science Foundation of China under Grant No.10275025
文摘A single-mode laser noise model driven by quadratic colored pump noise and biased amplitude modulationsignal is proposed.The analytic expression of signal-to-noise ratio is calculated by using a new linearized procedure.Itis found that there are three different typies of stochastic resonance in the model:the conventional form of stochasticresonance,the stochastic resonance in the broad sense,and the bona fide SR.
文摘This paper investigates the signal-to-noise ratio(SNR)driven by colored noise and weak input signals.Based on the Cauchy-Schwarz and Rayleigh quotients inequalities,an analytical expression of SNR is developed,and its upper band is closely related to the Fisher information of noise.For mimicking the colored noise,we adopt the first-order moving-average model and propose the optimal input signal waveform.The stochastic resonance effect in threshold systems is demonstrated for the Gaussian mixture colored noise.The obtained results will be interesting in the case of improving the nonlinear filter performance by adding noise to the weak signal corrupted by the colored noise.
文摘目的:分析彩色多普勒超声在双波长激光治疗婴幼儿血管瘤的应用价值。方法:回顾性分析2021年3月至2023年3月收治的血管瘤患者临床资料,所有患者在行Cynergy双波长激光治疗前均接受彩色多普勒超声检查,根据不同的血流信号和皮损深度,观察治疗效果及并发症发生情况。结果:198例血管瘤患儿纳入分析,共计212处皮损,其中根据血流信号分为无血流信号73例(34.3%)、稀少血流信号76例(35.8%)、中等血流信号63例(29.9%),有效率为100%,96.1%,85.7%,三组比较差异有统计学意义(P<0.05);根据皮损深度分为<1.2 mm 69例(32.5%),1.2~3.0 mm 88例(41.5%),>3 mm 55例(26.0%),有效率为100%,94.3%,83.6%,三组比较差异有统计学意义(P<0.05);在所有纳入的患者中,有21.7%的患儿出现不良反应。结论:彩色多普勒超声在双波长激光治疗婴幼儿血管瘤中具有重要的应用价值,可以实时监测治疗过程,并帮助临床医师预估疗效。
文摘In this paper, we propose extraction of signals correlated with noise in which they are buried. Proposed extraction method uses no a-priori information on the buried signal and works independently of the nature of noise, correlated or not with the signal, colored or white, Gaussian or not, and locations of its spectral extent. Extraction of buried correlated signals is achieved without averaging in the time or frequency domain.
文摘This letter demonstrates the structure of the passive radar using TV signals. Because the TV signal is a kind of pseudoperiodic signal, the matched filtering of color TV signals would yield high sidelobes which cause the range ambiguity. To overcome this problem, the mismatched filter is proposed to suppress the correlation sidelobes of matched filtering of TV signals. By utilizing the iteration process, this method could achieve the required peak sidelobe level. The impacts of the noise and target movement on mismatched filtering are also analysed. Simulation results are included to demonstrate the effectiveness of the proposed technique.
基金Supported by Doctoral Fund of the State Education Commission of China
文摘The cross-spectral estimation methods are efficient in estimating the parameters of sinusoidal signals embedded in colored noise. But up to now, only FPT and cross-periodogram methods are used in this field, the modern auto-spectral estimation method is introduced into cross-spectral estimation in this paper, meanwhile the cross-correlation based Yule-Walker equation is proposed theoretically and the moment and singular-value decomposition (SVD)) algorithms for cross-spectral estimation have been developed. Finally, a numerical example is given for comparing the presented methods with the well-known Cadzow’s SVD method.
文摘The phenomenon of stochastic resonance (SR) in a bistable nonlinear system is studied when the system is driven by the asymmetric potential and additive Gaussian colored noise. Using the unified colored noise approximation method, the additive Gaussian colored noise can be simplified to additive Gaussian white noise. The signal-to-noise ratio (SNR) is calculated according to the generalized two-state theory (shown in [H.S. Wio and S. Bouzat, Brazilian J.Phys. 29 (1999) 136]). We find that the SNR increases with the proximity of a to zero. In addition, the correlation time τ between the additive Gaussian colored noise is also an ingredient to improve SR. The shorter the correlation time τ between the Gaussian additive colored noise is, the higher of the peak value of SNR.
文摘In this paper, we propose extraction of signals buried in non-ergodic processes. It is shown that the proposed method extracts signals defined in a non-ergodic framework without averaging or smoothing in the direct time or frequency domain. Extraction is achieved independently of the nature of noise, correlated or not with the signal, colored or white, Gaussian or not, and locations of its spectral extent. Performances of the pro-posed extraction method and comparative results with other methods are demonstrated via experimental Doppler velocimetry measurements.
文摘针对色噪声下基于差分去噪的宽带相干信号波达方向(direction of arrival,DOA)估计方法对相干信源数有限制的问题,提出一种基于噪声圆形特性去噪和Toeplitz矩阵重构的估计算法。首先,对接收到的信号求取协方差矩阵,利用噪声的圆形特性消除噪声。为达到对协方差矩阵进行Toeplitz矩阵重构的要求,通过协方差矩阵相乘来构造新的数据协方差矩阵。然后,通过Toeplitz矩阵重构来解相干。最后,利用旋转子空间算法准则构造聚焦矩阵,使用传播算子算法实现DOA估计。理论分析及仿真实验验证了该算法的有效性,该算法对相干信源数的奇偶没有限制,同时该算法也适用于高斯白噪声下宽带相干信号DOA估计的场景。
