A real-time programmable switched-capacitor filter

Four independent real-time programmable switched-capacitor filters have been fabricated on a single NMOS chip. The filters are second-order sections with digitally programmable Q and center frequency. Either low-pass or bandpass functions are available by selecting the appropriate input. The device is microprocessor compatible and includes permanent programming capability as well as an on-chip oscillator. The circuit implementation, programming capability, and operation are described.     

An integrated real-time programmable transversal filter

Implementation, measurements, and characteristics of a fully integrated 32 tap real-time programmable transversal filter, which facilitates a number of filter applications, are discussed. It uses RAMs and 16 MDACs for tap weight programming and pipe organ structure to provide for a large variety of adaptive convolutional and correlative signal processing with optimum compromise among power dissipation, computational speed, size, and performance. The filter was constructed with the combined technology of bucket brigade devices and switched capacitors.     

基于FPGA的实时大窗口中值滤波器的设计

中值滤波在图像预处理阶段有着重要的应用,尤其是对于图像中脉冲噪声的滤除。传统的中值滤波算法都是通过对原数据按照大小排序,然后才能取出中值。但随着窗口尺寸的扩大,因数据增多而造成比较次数的激增,这成为制约大窗口中值滤波器实时性的一个瓶颈。针对这一问题,该文提出一种基于FPGA的25输入的实时中值滤波器的设计方法。无需对原数据进行大小排序,而是根据各比特平面的信息,重新生成一个中值,特别适合于FPGA实现。设计专用的位处理单元,简化了电路结构。通过三级查找表的方式,解决"多数表决器"耗时长的问题。实验结果表明,滤波器资源占用少,数据吞吐率高,延迟小,可满足任何窗口形状的滤波要求。     

A real-time learning algorithm for a multilayered neural networkbased on the extended Kalman filter

A novel real-time learning algorithm for a multilayered neural network is derived from the extended Kalman filter (EKF). Since this EKF-based learning algorithm approximately gives the minimum variance estimate of the linkweights, the convergence performance is improved in comparison with the backwards error propagation algorithm using the steepest descent techniques. Furthermore, tuning parameters which crucially govern the convergence properties are not included, which makes its application easier. Simulation results for the XOR and parity problems are provided     

Hybrid realisation of an adaptive filter for real-time noise-cancelling applications

An efficient hybrid realisation of an adaptive filter for real-time noise-cancelling applications is described. The filter is based on an analogue tapped delay line but its coefficients are digital and are updated according to a simplified l.m.s. algorithm. A single multiplying d.a. device is used for performing the multiplications. The structure of the filter, its performance and processed examples are presented.     

基于LabVIEW的实时数据采集和滤波处理设计

磨损是影响机械设备工作可靠性和使用寿命的主要因素之一,摩擦磨损产生的磨粒是反映设备内部磨损状况的重要载体,因此对油路中磨粒特性的监测是对机械设备进行状态监测与故障诊断的一个重要手段。本设计通过采用虚拟仪器技术,使用LabVIEW图形化编程软件和NI公司的PCI-1200数据采集卡,并结合油路磨粒检测信号的特征,设计了一...     

DSP implementation of real-time MPEG-2 audio decoder using novelsynthesis filter bank

An efficient synthesis filter is presented which can carry out real-time MPEG-2 audio decoding. The proposed algorithm reduces the number of MAC operations by adopting novel IDCT and windowing schemes, exploiting a multichannel structure, and implementing CGD techniques. The DSP implementation is MPEG-2 compliant and achieves real-time processing with 60% reduction in run-time compared with a fast ISO decoder     

基于单片机的UHF电调滤波器的实时调谐设计

为实现多部通信机在近距离内以邻近的频率互不干扰的正常工作,有效方法就是在接收机的输入端和输出端接入具有实时调谐功能的窄带高Q滤波器.提出了基于单片机的UHF电调滤波器的实时调谐设计,给出硬件结构图以及驱动和检测单元电路,并给出设计流程.     

An orthogonal least squares-based fuzzy filter for real-time analysis of lung sounds

Pathological discontinuous adventitious sounds (DAS) are strongly related with the pulmonary dysfunction. Its clinical use for the interpretation of respiratory malfunction depends on their efficient and objective separation from vesicular sounds (VS). In this paper, an automated approach to the isolation of DAS from VS, based on their nonstationarity, is presented. The proposed scheme uses two fuzzy inference systems (FISs), operating in parallel, to perform the task of adaptive separation, resulting in the orthogonal least squares-based fuzzy filter (OLS-FF). By applying the OLS-FF to fine/coarse crackles and squawks, selected from three lung sound databases, the coherent structure of DAS is revealed and they are efficiently separated from VS. The important time domain DAS features, related to diagnostic information, are preserved and their true location and structural morphology are automatically identified. When compared to previous works, the OLS-FF performs quite similarly, but with significantly lower computational load, resulting in a faster real-time clinical screening of DAS.     

光学模式识别实时硬件执行系统滤波器综合技术

本文介绍了一种光学模式识别(OPR)实时硬件执行系统滤波器综合的新方法。采用该方法,在综合判别函数(SDF)畸变不变相关滤波系统中实现了系统性能优化,得到了最小相关峰值方差及最佳S/N的相关输出。     

Hardware implementation of a spatio-temporal average filter for real-time denoising of fluoroscopic images

An electronic system for the real-time denoising of fluoroscopic images is proposed in this paper. Fluoroscopic devices use X-rays to obtain real-time moving images of patients and support many surgical interventions and a variety of diagnostic procedures. In order to avoid risks for the patient, X-ray intensity has to be kept acceptably low during the clinical applications. This implies that fluoroscopic images are corrupted by large quantum noise (Poisson-distributed). Real-time noise reduction can offer a better visual perception to doctors and possible further reductions of the dose.The proposed circuit implements a spatio-temporal filter optimized for the removal of the quantum noise while preserving video edges and the prompt response of the image to the introduction of new features in the field. The filter incorporates information on the dependence of the standard deviation of the noise on the local brightness of the image and performs a conditioned average operation.The proposed circuit is implemented on FPGA (Field Programmable Gate Array) device allowing the real time elaboration of video streams composed by frames with 1024×1024 pixel and uses an external DDR2 (Double Data Rate 2) memory for the storage and the reuse of the fluoroscopic frames needed by the filter.When implemented on StratixIV-GX70 FPGA the circuit is able to process up to 49 fps (frames per second) while using 80% of the logic resources of the FPGA.     

A monolithic adaptive filter

Reports a monolithic adaptive filter which has been realized using purely analog sampled-data MOS and CCD techniques. The filter implements a full Widrow least mean-squares algorithm over 65 data points. Central to this design is a novel, compact analog multiplier/accumulator circuit, which is presented in detail. The 65-point adaptive filter, which is cascadable, dissipates 200 mW from a 15 V supply, and operates at sample rates up to 100 kHz.     

一种类正余弦CIC滤波器

传统CIC滤波器由于其实现不需要乘法器和存储器,因此已在各种变采样率系统中得到了广泛的应用。但是传统CIC滤波器的通带失真较大,阻带衰减较小,而且其积分器工作在高采样率端,这很大程度限制了它在对性能要求较高的变采样率系统中的应用。而后来提出的各种CIC滤波器,如锐化CIC滤波器、ISOP-CIC滤波器和CIC-Cosine滤波器等,或者只改善通带特性,或者只改善阻带特性,或者积分器运行在高采样率端。本文在分析对比了传统的CIC滤波器、锐化CIC滤波器、ISOP-CIC滤波器和CIC-Cosine滤波器的频率特性的基础上,引入一种类余弦预滤波器和一种类正弦预滤波器,再加上多级级联的传统CIC滤波器,构成一种多级结构的类正余弦CIC滤波器。所引入的类正弦预滤波器和类余弦预滤波器分别用于减小CIC滤波器的通带失真和增大其阻带衰减。仿真结果表明,所提出的类正余弦CIC滤波器比传统的CIC滤波器、ISOP-CIC滤波器、CIC-Cosine滤波器都具有更小的通带失真和更大的阻带衰减。同时所引入的两级预滤波器工作在低采样率端,并且通过使用多相分解技术同样可使多级级联的CIC滤波器工作于低采样率端。      

A real-time photoluminescence imaging system

We have developed a real-time photoluminescence imaging system. In contrast to scanning systems, in our set-up the photoluminescence is excited over theentire area of a sample at once. The intensity of the spectrally resolved emission from the whole sample is monitored and displayed in real-time, in a color-coded format. This system can be used for the quick inspection of optical and electro-optical materials, and is promising for in-situ characterization. As an example for the performance of the system we show data obtained on a GaAs/AlGaAs p-i-n quantum well modulator, and on an InP substrate.     

A real-time electrical impedance tomograph

Electrical properties of tissues in the human body can be imaged using a technology known as Electrical Impedance Tomography. In this modality, sinusoidal electrical currents are applied to the body using electrodes attached to the skin, and voltages that are developed on the electrodes are measured. Using these data, a reconstruction algorithm computes the conductivity and permittivity distributions within the body. This paper describes the reconstruction algorithm, image display algorithm, and hardware of a real-time Electrical Impedance Tomograph known as the Real-Time Imaging System. The reconstruction algorithm, executed by a commercially available coprocessor board that resides in a 386-based personal computer, is a modification of the Newton's One Step Error Reconstructor (NOSER) that minimizes algorithm execution time by precomputing many quantities. The image display algorithm, also executed by the coprocessor board, maps the output of the reconstruction algorithm into an image which is displayed using a video graphics board. The architecture of the system and execution times of algorithms implemented by the system are discussed. Using the continuous data acquisition mode of the Real-Time Imaging System, data from the thorax of a normal human subject were collected. Admittivity changes in the chest, as a result of respiration and the cardiac cycle, are presented. Data that were collected from the leg of a normal subject are shown which demonstrate capabilities of the triggered data acquisition mode of the system, allowing data acquisition synchronization with an electrocardiogram     

A self-timed real-time sorting network

High-speed networks are expected to carry traffic classes with diverse quality of service (QoS) guarantees. For efficient utilization of resources, sophisticated scheduling protocols are needed; however, these must be implemented without sacrificing the maximum possible bandwidth. This paper presents the architecture and implementation of a self-timed real-time sorting network to be used in packet switches that support a diverse mix of traffic. The sorting network receives packets with appropriately assigned priorities and schedules the packets for departure in a highest-priority-first manner. The circuit implementation uses zero-overhead, self-timed, and self-precharging domino logic to minimize the circuit latency. An experimental sorting network chip has been designed using the techniques described in this paper to support 10 Gb/s links with ATM-size packets     

A new charge routing filter

A fully integrated recursive charge transfer multibridge filter (MBF) is described using the concept of passive recirculation of charges. This is a novel solution for voice channel filters in digital communications. The MBF is constituted of a recursive routing structure and of a split electrode array. The structure behavior is investigated in terms of its state variables. Preliminary experimental results are reported on 13-bridge and 9-bridge filters.     

A hybrid ferrimagnetic-dielectric microwave filter

This paper describes a low-loss tunable dielectric resonator band bandpass filter for the frequency range 1 to 12 GHz. The filters are mechanically and/or magnetically tuned. Mode splitting, due to coupling between dimensional dielectric resonances with ferrimagnetic modes, and heat sinking techniques significantly improve the power-handling capabilities.     

A multistub filter for microstripline

A maximally flat multistub filter was designed using both λ/4 shorted and λ/2 open stubs and constructed on ceramic substrate using microstrip transmission lines.