A new non-uniform adaptive-sampling successive approximation ADC for biomedical sparse signals

This paper presents a new sampling technique and a successive approximation analog to digital converter (SA-ADC) which samples sparse signals in a non-uniform adaptive way. The proposed sampling technique has the capability to be incorporated in the structure of the SA-ADC. The proposed SA-ADC changes the rate of sampling in accordance with the rate of changes of the signal. In this way, the data volume is reduced considerably without losing the important information in the signal. Simulation results in the 0.18 um CMOS technology shows a power saving of up to 90.5 % and a compression ratio of 7.5 compared to the conventional sampling technique of ECG signals.     

一种抑制OFDM信号峰均功率比的新优化算法

为了降低正交频分复用系统的峰均比，提出了一种将部分传输序列（PTS）算法与限带抵消技术相级联的新算法。该算法首先利用F1S算法，对系统PAPR特性优化，然后利用限带抽样信号作为参考函数，实现对系统峰均功率比的进一步有效降低。文中给出PTS级联抵消技术的原理和算法，并分析了在不同抵消程度基础上系统的PAPR性能。仿真结果表明，此种方法仅以微小的误码率性能为代价，有效降低正交频分复用系统的峰均功率比。     

一种新的卫星信号调制方式识别方法

根据采样数据恢复信号频谱后,采用频域估计法检测卫星信号中心频率,再利用延 迟相乘法估计卫星信号调制速率。通过内插恢复得到信号星座图,根据星座图特征对无先验 信息的卫星信号调制方式进行识别。利用实测的8PSK和QPSK卫星信号检测了识别的效果, 在信号信噪比低于5 dB时无法得到信号星座图。     

一种新的改善激光声信号特性的方法

为了改善激光声信号的特性,设计了激光声换能器。对换能器的设计原理和结构进行了说明。构建了激光声实验系统,利用脉冲激光分别在自由场和换能器内部聚焦击穿水介质产生声信号,由水听器将声信号转换成电信号并送入数字存储示波器。对两种条件下产生的激光声信号特性进行了比较。结果表明:同自由场产生的激光声信号相比,利用换能器产生的激光声信号特性有了一定程度的改善。其中,信号峰值幅度提高了3 倍,能量向60 kHz 以下频段集中,1m处发散角压缩到13.2,衰减速度变慢。     

A new peak detection method for the three-phase sinusoidal signals

An instantaneous amplitude detection method for the three-phase sinusoidal signals is proposed. The proposed method can measure the amplitude of the three-phase signals without any delay by using only two of the three-phase signals. The performance of this method under the ideal and nonideal conditions is analyzed. To demonstrate the performance of the proposed method, an electronic circuit for implementing this method is developed and tested     

A new extrapolation algorithm for band-limited signals using theregularization method

The ill-posedness of the extrapolation problem in the presence of noise is considered. A stable algorithm is constructed by solving a Fredholm equation based on a regularization method. The algorithm appears relatively robust, since the noise η_δ(t ) is taken as a function in L²[-T,T](T>0) such that the error energy ∫|η_δ(t)|² dt⩽δ², where integration is from - T to T, and the constructed extrapolation uniformly converges to the desired signal over (-∞, +∞) as δ→0. An estimate for the error energy of the constructed extrapolation over (-∞, +∞) and for the absolute error between the constructed extrapolation and the desired signal over (-∞, +∞) are presented     

一种新的电能质量扰动特征提取与识别方法

为了克服电能质量扰动识别时由于特征选择和提取不当造成最后识别精度低的缺点,提出一种基于数学统计的电能质量扰动幅值采样点数的特征提取方法和PSO-SVM电能质量扰动识别新方法。该方法根据10个周波信号的幅值差异,统计每段幅值范围内的采样点数,对其进行处理后作为各扰动信号的特征,然后采用PSO-SVM分类器对多种扰动信号进行分类识别。该方法特征提取的过程简单,减少了大量的计算处理时间。仿真实验结果表明,该方法能快速地识别出各种扰动信号,且识别精度高于传统方法并具有较好的抗噪声性能。     

A new method of spectral analysis and sample rate reduction for band-limited signals

A new method for spectrum analysis and sample rate reduction based upon the classical sampling theorem is presented. It is shown that bandshifting sinusoids are not required for frequency translation. This results in efficient implementations for bandpass spectral analysis.     

波达方向估计中的宽带信号个数检测新方法

在进行波达方向估计时,往往要对信号个数进行判断,传统的宽带信号个数检测方法需要在每个频点上进行多次采样,否则无法正确完成测向.针对此问题,提出了一种基于Bootstrap准则实现的宽带信号个数检测新方法.将宽带信号划分为若干个互不重叠的子带部分,之后对每个子带信号进行特征分解,利用特征值对相应的特征向量进行加权,再通过Bootstrap准则构造新的信号重采样矩阵,用聚类的方法判断出该子带上的信号个数,最后将各个子带上的结果进行综合判断出宽带信号个数.所提方法回避了聚焦的过程,且在非高斯噪声背景下也有较高的估计成功概率,尤其是在小快拍数下有着较好的估计性能,仿真结果证明了该方法的性能.     

一种复用传输射频和基带信号的新方法

介绍了一种在同轴电缆上,射频和基带信号复用传输的新方法。设计了射频信号和基带信号隔离电路,采用C-MBUS标准传输基带信号,在长为1 km、传输射频信号功率为40 d Bm的同轴电缆上,达到了4 800 b/s的数据传送速率,且同时可以为通信从机节点提供10 m A的电流。该方法具有硬件电路简单、成本低廉,容易组网的优点,适用于在射频线路上同时传输低数据速率的附加信息。     

一种强噪声背景下弱信号检测的非线性方法

该文利用随机共振技术对工程测量中常碰到的弱信号检测进行了计算机仿真,就信噪比的提高、弱信号的检测等进行了研究。并对信号经随机共振系统处理和不经随机共振系统处理进行检测比较。实验结果表明,随机共振技术完全有可能成为信号检测中一个强有力的新工具。     

一种新的宽带信号DOA估计算法

本文针对均匀线性阵列,在正交投影子空间(TOPS)算法的基础上,提出了一种新的宽带非相关和相干信号的DOA估计算法。首先,利用TOPS算法直接估计出宽带非相关信号的DOA;其次,在各个频率点,使用空间差分技术消除非相关信号和噪声的分量,并构造新矩阵;最后,对新矩阵进行空间平滑操作,再利用TOPS算法估计出宽带相干信号的DOA。由于分开估计宽带非相关信号和相干信号的DOA,算法适用于信号个数多于阵元个数的场合。计算机仿真结果证明了算法的有效性。     

WB-KNN for emotion recognition from physiological signals

K-nearest neighbor (KNN) has yielded excellent performance in physiological signals based on emotion recognition. But there are still some issues:the majority vote only by the nearest neighbors is too simple to deal with complex (like skewed) class distribution; features with the same contribution to the similarity will degrade the classification accuracy; samples in boundaries between classes are easily misclassified when k is larger. Therefore, we propose an improved KNN algorithm called WB-KNN, which takes into account the weight (both features and classification) and boundaries between classes. Firstly, a novel weighting method based on the distance and farthest neighbors named WDF is proposed to weight the classification, which improves the voting accuracy by making the nearer neighbors contribute more to the classification and using the farthest neighbors to reduce the weight of non-target class. Secondly, feature weight is introduced into the distance formula, so that the significant features contribute more to the similarity than noisy or irrelevant features. Thirdly, a voting classifier is adopted in order to overcome the weakness of KNN in boundaries between classes by combining different classifiers. Results of WB-KNN algorithm are encouraging compared with the traditional KNN and other classification algorithms on the physiological dataset with a skewed class distribution. Classification accuracy for 29 participants achieves 94.219 2% for the recognition of four emotions.     

一种偏移载波调幅信号的频域优选新方法

为了解决民航地空通信中机载电台接收到的多个偏移载波调幅信号互相干扰的问题,提出了一种在频域进行最佳载波搜索的优选方法。该方法采用能量重心法对接收信号的频谱幅度和频率进行校正,通过搜索频谱幅度的最大值,优选出一路载噪比最高的调幅信号进行解调,同时对其他调幅信号进行抑制。仿真实验和电台通信实验均表明该方法可以正确地实现多个偏移载波调幅信号的优选和解调,明显降低干扰,解调后话音的平均意见分提高了3分,具有实际工程应用价值。     

A parameter estimation scheme for damped sinusoidal signals basedon low-rank Hankel approximation

Most of the existing algorithms for parameter estimation of damped sinusoidal signals are based only on the low-rank approximation of the prediction matrix and ignore the Hankel property of the prediction matrix. We propose a modified Kumaresan-Tufts (MKT) algorithm exploiting both rank-deficient and Hankel properties of the prediction matrix. Computer simulation results demonstrate that compared with the original Kumaresan-Tufts (1982) algorithm and the matrix pencil algorithm, the MKT algorithm has a lower noise threshold and can estimate the parameters of signal with larger damping factors     

利用干涉原理估计相干信号DOA的新方法

利用干涉原理估计相干信号波达方向(DOA)的新方法，对参考阵元的数据延时，且时延是可调的，则天线阵输出功率为时延的函数，该功率函数可以展开为三角函数的级数形式，其展开系数即为信号DOA的三角函数。通过对三阵元天线阵仿真表明，该方法计算量很小，即使在小样本，低信噪比(SNR)时，也能很好地估计相干信号DOA。     

A new method for estimating the acoustic attenuation coefficient of tissue from reflected ultrasonic signals

The parameter characterizing the acoustic attenuation in soft tissues is an indicator of tissue state. A method which features autoregressive deconvolution and spectral smoothing is proposed for estimation of the parameter from ultrasonic signals reflected from the tissue. The results of simulation and of processing actual liver data show that the standard deviation of the estimation is approximately halved by this method, compared to the traditional spectral differences method.     

A new preconditioner based on paraxial approximation for stable and efficient reflective beam propagation method

We present a preconditioner based on the paraxial approximation for the square-root operator to realize a stable and efficient iterative scheme in the reflective beam propagation method. The new preconditioner is shown to be highly effective in facilitating robust, efficient, and accurate solutions for computation of reflected and transmitted fields due to index discontinuities along optical waveguides, due primarily to the improvement on the condition number of the operator used.     

基于广义延拓逼近的GPS卫星信号多普勒频移估计方法

对并行码相位捕获GPS卫星信号时多普勒频移的栅栏效应进行研究。为了减小栅栏效应的影响,提高多普勒频移的捕获精度,提出用广义延拓逼近法来提高多普勒频移的估计精度,并在不增加算法运算量的基础上,对此方法进行优化,进一步降低了噪声对捕获多普勒频移精度的影响,仿真结果验证了该方法的有效性。     

A new approximation and a new measurable constraint for slabprofile inversion

A new approximation and a new measurable constraint for slab profile inversion is introduced. A comparison is given between the Born, the exact, and the new approximation. The new approximation and constraint can be utilized along with other methods such as the integral equation, the iterative or perturbed Born, and the alternating projection approaches. The latter is considered. The results obtained are superior to those obtained under the Born approximation