Combined switched-capacitor FIR N-path filter using only grounded capacitors

A simple technique is presented that allows the unwanted sidebands of an N-path filter to be suppressed. The circuit realising this technique uses only grounded capacitors.     

差分时钟增益提高型N通道带通滤波器设计

针对传统N通道滤波器存在增益以及时钟的偶次谐波对滤波性能产生不利影响的问题,利用增益提高技术和差分时钟技术提出了一种增益提高型、时钟偶次谐波消除的N通道带通滤波器。在TSMC 90 nm工艺参数和1.2 V电源电压下对其进行Spectre模拟。结果表明,滤波器的增益高于9.8 dB,中心频率可调范围为0.2~2.2 GHz,S11>10 dB,IIP3>11 dB,阻带抑制为26 dB。电路结构简单,仅由反向器、开关和电容组成,且易于集成。     

Dynamic multi-cue tracking using particle filter

We consider the problem of decomposing audio into components that have different time frequency characteristics. For this, we model the components using different transforms and mixed norms applied on the transform domain coefficients. We formulate the problem as a search for a saddle point and derive algorithms through a primal-dual framework. We also discuss how to modify the primal-dual algorithms in order to derive a simpler heuristic scheme.     

Threshold region of f.d.m./f.m. signals

Although many papers have been published concerning the analysis of the threshold region of f.m. signals, they are all incomplete. The present letter introduces a new analysis, in which the carrier is modulated by a Gaussian baseband signal, and gives important results which cannot be deduced from previous analyses.     

Response of a recursive m.t.i. filter to inputs with staggered p.r.f.

The authors present graphical results of computer simulations showing that proper choice of feedback coefficients in conjunction with a staggered p.r.f.input can achieve significant improvements in low-frequency cutoff and in smoothness of response within the passband, at the expense of increased circuit complexity.     

Realisation of a 2-dimensional f.i.r. digital filter using separable filters

The scheme for the expansion of a 2-dimensional f.i.r. digital filter function into a sum of separable functions is generalised. Using the generalised procedure a m × m order filter function can be expressed in as many as m!n!/(|m?n| + 1)! ways. Further it is also proved that the number of terms in the expansion will be equal to the rank of the matrix.     

Video object tracking using adaptive Kalman filter

In this paper, a new video moving object tracking method is proposed. In initialization, a moving object selected by the user is segmented and the dominant color is extracted from the segmented target. In tracking step, a motion model is constructed to set the system model of adaptive Kalman filter firstly. Then, the dominant color of the moving object in HSI color space will be used as feature to detect the moving object in the consecutive video frames. The detected result is fed back as the measurement of adaptive Kalman filter and the estimate parameters of adaptive Kalman filter are adjusted by occlusion ratio adaptively. The proposed method has the robust ability to track the moving object in the consecutive frames under some kinds of real-world complex situations such as the moving object disappearing totally or partially due to occlusion by other ones, fast moving object, changing lighting, changing the direction and orientation of the moving object, and changing the velocity of moving object suddenly. The proposed method is an efficient video object tracking algorithm.     

The measurement of f.m. noise from Gunn oscillators using a microwave interferometer

An alternative method of measuring the f.m. noise of an X-bond Gunn oscillator is described. With the use of a length of microwave delay line and an adjustable phase shifter, the measuring system can be used for different microwave frequencies without the need of elaborate adjustments. The frequency discrimination sensitivity can be maximized by proprrly selecting the length of the delay line. Under such conditions, the video bandwidth of the system is just over 1 MHz. Measurements made using this method generally confirm that Gunn oscillators exhibit 1/f noise at low frequencies in addition to the wide-band thermal noise.     

仅测角卫星跟踪的扩展卡尔曼粒子滤波算法

卫星被动跟踪技术对于空间监视系统非常重要,为提高非合作跟踪模式下空间低轨卫星(LEO)的跟踪精度,提出一种基于扩展卡尔曼粒子滤波(EKPF)的仅测角卫星被动跟踪算法.首先,在卫星二体运动下,以地球惯性直角坐标系为基础,对卫星运动状态方程的二阶线性化、状态方程和测量方程的雅可比矩阵进行了详细推导.其次,利用二阶扩展卡尔曼...     

Real-time speaker tracking using particle filter sensor fusion

Sensor fusion for object tracking has become an active research direction during the past few years. But how to do it in a robust and principled way is still an open problem. In this paper, we propose a new fusion framework that combines both the bottom-up and top-down approaches to probabilistically fuse multiple sensing modalities. At the lower level, individual vision and audio trackers are designed to generate effective proposals for the fuser. At the higher level, the fuser performs reliable tracking by verifying hypotheses over multiple likelihood models from multiple cues. Unlike traditional fusion algorithms, the proposed framework is a closed-loop system where the fuser and trackers coordinate their tracking information. Furthermore, to handle nonstationary situations, the proposed framework evaluates the performance of the individual trackers and dynamically updates their object states. We present a real-time speaker tracking system based on the proposed framework by fusing object contour, color and sound source location. We report robust tracking results.     

Influence of the channel width on the threshold voltage modulation in m.o.s.f.e.t.s

The threshold vollage of an m.o.s. field-effect transistor is modulated by the source-to-substrate reverse bias. In the letter, the theory for long- and short-channel transistors is extended to include the influence of the channel width. The result is an analytical expression for the threshold voltage as a function of geometry and bias that agrees well with experimental data.     

改善高精度数字闭环光纤陀螺阈值方法研究

研究了改善高精度光纤陀螺阈值的方法,提出导致阈值增大的原因是陀螺存在死区,而死区主要由调制解调电路中的电子交叉耦合干扰引起。对光纤陀螺仪的数字闭环传递模型进行了修正,增加了反馈通道对前向通道中探测器输出信号的电子交叉耦合干扰项,并利用此模型对死区进行了实时动态仿真,仿真分析结果基本和实验现象吻合。与采取随机调制的方法不同,本文主要采取优化电子电路设计、改善电路电磁兼容性等方法抑制死区,同样取得了较好的效果。提出了一种新的测试光纤陀螺仪的阈值方法,测试结果表明,优化设计后,陀螺仪的阈值与陀螺的噪声水平相当。     

Intermodulation in an f.m. oscillator injection locked by an f.m. signal

Analysis of injection locking by f.m. signals is presented when the locked oscillator and the locking source are frequency modulated by the same signal. Intermodulation noise and optimum deviation of the locked oscillator are derived, assuming f.m. by band-limited Gaussion noise. Previous published results and recent experiments confirm the results obtained.     

Rectangular-wave modulation?a hybrid p.l.m.?f.m. system

Using an equal-slope approximation of signal waveforms, a new method of coding complex signals with on?off pulses of varying width and repetition period has been developed. The distortion and channel-noise characteristics of the system are similar to those of an equivalent f.m. system. The noise threshold improves on using vestigial-sideband a.m. and p.m. techniques in r.f. channels.     

Etched Schottky-barrier m.o.s.f.e.t.s using a single mask

A simplified method for fabricating silicon m.o.s. transistors using a single photographic mask is described. The source and drain regions are etched; underetching the oxide results in autoregistration of the gate. The characteristics of both Schottky-barrier and p?n junction source and drain devices are presented.     

Occlusion-robust online multi-object visual tracking using a GM-PHD filter with CNN-based re-identification

We propose a novel online multi-object visual tracker using a Gaussian mixture Probability Hypothesis Density (GM-PHD) filter and deep appearance learning. The GM-PHD filter has a linear complexity with the number of objects and observations while estimating the states and cardinality of time-varying number of objects, however, it is susceptible to miss-detections and does not include the identity of objects. We use visual-spatio-temporal information obtained from object bounding boxes and deeply learned appearance representations to perform estimates-to-tracks data association for target labeling as well as formulate an augmented likelihood and then integrate into the update step of the GM-PHD filter. We also employ additional unassigned tracks prediction after the data association step to overcome the susceptibility of the GM-PHD filter towards miss-detections caused by occlusion. Extensive evaluations on MOT16, MOT17 and HiEve benchmark data sets show that our tracker significantly outperforms several state-of-the-art trackers in terms of tracking accuracy and identification.     

Feasibility of using digital filters to interconnect p.c.m. and f.d.m. transmission systems

A time-division multiplex (t.d.m.) and a frequency-division multiple (f.d.m.) system may be interconnected by means of gates and lowpass filters. The use of digital filters (d.f.s) for this purpose appears attractive when the t.d.m. system uses pulse-code modulation (p.c.m.), because digital-analogue and analogue-digital conversion are unnecessary at the interface between the d.f. and the p.c.m. system. The problems involved in applying d.f.s in this application are discussed. It is concluded that the interconnection of p.c.m. systems with f.d.m. systems using quite low carrier frequencies requires the development of digital circuits operating at several hundred megahertz.     

基于无线层析成像和卡尔曼滤波的定位追踪

无线传感网的无源定位问题对现实社会有着重要意义,通过对局域范围内的RSSI进行捕捉,并根据RSSI的变化在区域内的衰减,再依据线型模型进行计算,从而得到局域范围内的位置坐标。将每次采样得到的位置坐标信息进行预处理,再通过卡尔曼滤波进行优化,从而形成物体运动的轨迹。     

Dynamic f.m.-discriminator distortion

The demodulation of an f.m. signal introduces both static and dynamic distortion. This letter presents a 1st-order approximation to the latter, and determines the spectrum of the intermodulation resulting from both effects. This analysis is based on the van der Pol-Stumpers expansion of a filter's response to an f.m. wave.