Revisiting the doppler filter of LEO satellite GNSS receivers for precise velocity estimation

The theoretical aspects of the precise velocity determination of Low Earth Orbit (LEO) satellites’on board Global Navigation Satellite Systems (GNSS) receivers are derived. It shows that the receiver’s Phase Lock Loop (PLL) is required to feature extremely small group delay within its low frequency band, which is in contrast to existing work that proposed wide band linear phase filters. Following this theory, a Finite Impulse Response (FIR) filter is proposed. To corroborate, the proposed FIR filter and an Infinite Impulse Response (IIR) filter lately proposed in literals are implemented in a LEO satellite onboard GNSS receiver. Tests are conducted using a third party commercial GPS signal generator. The results show that the GNSS receiver with the proposed FIR achieves 11 mm/s R.M.S precision, while the GNSS receiver with the IIR filter has a filter-caused velocity error that can not be ignored for space borne GNSS receivers.     

基于MATLAB的高性能半带滤波器设计

在数字滤波器的设计中,为了能够有效地进行抽取滤波,往往采用多级抽取的方法。文中引入一种半带FIR（有限冲激响应）滤波器来实现多级抽取。半带滤波器是一种特殊的低通FIR数字滤波器,它的通带和阻带关于二分之一Nyquist频率对称,因而有近一半的滤波器系数为0,所以用它来实现数字滤波可以大幅度地减少运算量,有利于滤波器的实时实现。半带FIR滤波器主要应用于多速率系统中,可以提高系统的效率。剖析了半带FIR滤波器的原理、性质及实现的方法,给出了基于MATLAB和QuartusⅡ联合的半带FIR滤波器的设计仿真过程,并对结果进行了分析。     

Fast Implementation of 3-D Digital Filters Via Systolic Array Processors

In this paper a fast implementation architecture of three-dimensional (3-D) FIR or IIR digital filters via systolic VLSI array processors is described. The modular structure presented is comprised of similar processing elements in a linear cascade configuration with local interconnections. High speed throughput rates are attained due to high concurrency, which is achieved by exploiting both pipelining and parallelism. The considered 3-D FIR and IIR filters may be used for the processing of reconstructed 3-D images and in medical imaging applications.     

Model and performance analysis of FMT system and orthogonal filterbanks

An orthogonal multi-carrier modulation—Filtered Multi-Tone (FMT) modulation, is evaluated in this paper. The objective of this paper is to model the FMT system with polyphase fil- terbank network, design its synthesis/analysis orthogonal filterbanks and analyze their performance. Oversampled and critically sampled cases of FMT system are discussed in detail. Perfect Reconstruc- tion (PR) properties of M parallel orthogonal subchannels in the case of critically sampled is derived from filterbank polyphase de...     

An iterative algorithm for optimal design of non-frequency-selective FIR digital filters

This paper proposes a novel iterative algorithm for optimal design of non-frequency-selective Finite Impulse Response （FIR） digital filters based on the windowing method. Different from the traditional optimization concept of adjusting the window or the filter order in the windowing design of an FIR digital filter, the key idea of the algorithm is minimizing the approximation error by successively modifying the design result through an iterative procedure under the condition of a fixed window length. In the iterative procedure, the known deviation of the designed frequency response in each iteration from the ideal frequency response is used as a reference for the next iteration. Because the approximation error can be specified variably, the algorithm is applicable for the design of FIR digital filters with different technical requirements in the frequency domain. A design example is employed to illustrate the efficiency of the algorithm.     

基于FIR与相位补偿IIR滤波器的雷达回波信号处理

FIR与IIR频率选择滤波器的设计,被广泛应用于数字信号处理领域之中。文章以雷达回波信号的数字处理为例,首先分别设计FIR,IIR滤波器完成了对信号特定频率分量的滤除。进而,针对IIR滤波器的非线性相位,基于最优化设计全通系统实现了相位补偿,并对FIR,IIR滤波器进行了综合比较。     

A bit-slice architecture for sigma-delta analog-to-digitalconverters

The sigma-delta analog-to-digital converters is based on filtering and undersampling by the digital section of the one-bit output stream coming from the modulation. The structure of this section, consisting of a sine cubic FIR filter decimator followed by an IIR decimator section, is discussed. It is shown that from both signal processing and hardware implementation viewpoints it is advantageous to have the decimation factor of the first stage as large as possible. A bit-slice implementation of the decimation stages is given. It can be easily expanded when higher bit resolutions are required     

无线寻呼系统中窄带FSK调制的实现

简要介绍了无线寻呼系统中 FSK (Frequency Shift Keying)调制技术及其硬件的实现基础 DDS (Direct DigitalSynthesis)的基本工作原理 ,进而提出了一种利用 DSP (Digital Signal Processor)实现 FIR (Finite Im pulse Re-sponse)滤波器 ,以改善 FSK调制频谱性能的方案 ,最后给出了实验电路的框图。     

A new method for adaptive IIR filter design based on tabu search algorithm

Adaptive digital filters have proven their worth in a wide range of applications such as channel equalisation, noise reduction, echo cancelling, and system identification. These filters can be broadly classified into two groups: finite impulse–response (FIR) and infinite impulse–response (IIR) filters. IIR filters have become the target of increasing interest because these filters can reduce the filter order significantly as compared to FIR filters. Tabu search is a heuristic optimisation algorithm which has been originally developed for combinatorial optimisation problems. It simulates the general rules of intelligent problem solving and has the ability of discovering the global minima in a multi-modal search space. In this work, a novel method based on tabu search is described for the design of adaptive IIR filters.     

一种用于基因预测的FIR数字滤波器

数字信号处理技术已经用于DNA(DeoxyriboNucleic Acid)序列中的基因分析与识别.本文利用数字滤波器对基因序列进行分析和预测,根据基因序列周期3bp(base pair),设计了一种具有窄带选通特性的FIR(Finite Impulse Response)数字滤波器,对基因序列进行滤波,与IIR(Infinite Impulse Response)数字滤波器计算的结果对比,获得了较好的仿真结果.     

A new adaptive recursive RLS-based fast-array IIR filter for active noise and vibration control systems

Infinite impulse response filters have not been used extensively in active noise and vibration control applications. The problems are mainly due to the multimodal error surface and instability of adaptive IIR filters used in such applications. Considering these, in this paper a new adaptive recursive RLS-based fast-array IIR filter for active noise and vibration control applications is proposed. At first an RLS-based adaptive IIR filter with computational complexity of order O(n²) is derived, and a sufficient condition for its stability is proposed by applying passivity theorem on the equivalent feedback representation of this adaptive algorithm. In the second step, to reduce the computational complexity of the algorithm to the order of O(n) as well as to improve its numerical stability, a fast array implementation of this adaptive IIR filter is derived. This is accomplished by extending the existing results of fast-array implementation of adaptive FIR filters to adaptive IIR filters. Comparison of the performance of the fast-array algorithm with that of Erikson’s FuLMS and SHARF algorithms confirms that the proposed algorithm has faster convergence rate and ability to reach a lower minimum mean square error which is of great importance in active noise and vibration control applications.     

用于太赫兹高速通信的FIR滤波器64并行实现算法

为满足太赫兹无线通信系统对大容量基带信号处理算法的要求,基于直接从多项式分解导出的传统滤波器并行实现算法,通过矩阵变化推导出复杂度更小的快速有限冲激响应(FIR)滤波器并行实现。在此基础上通过张量积的表示给出了2并行、4并行和8并行的转换公式以及实现架构。既而推导出2N并行快速FIR滤波器的通用实现公式,并对比了优化前后的复杂度差异。最后给出了64并行的快速FIR滤波器的推导公式和具体实现架构,以及优化前后的硬件复杂度对比,64并行的快速FIR滤波器算法资源消耗更少。     

FIR数字滤波器的设计与实现

在数字信号处理中,数字滤波器是一种被广泛使用的信号处理部件。分析了FIR(有限冲激响应)数字滤波器的结构特征,得到了满足系统要求的数字滤波器设计方法,结合实际工程所要求的数字滤波器指标,利用MATLAB对FIR数字滤波器进行了设计和仿真,并根据FIR数字滤波器输出的幅频特性和相频特性图对滤波器的参数进行调整,从而得到满足性能要求的最佳数字滤波器参数。采用DSP芯片实现所设计的FIR数字滤波器。     

基于数字滤波的计算机视频信息防泄漏研究

 本文针对计算机视频信息泄漏,提出了一种基于数字滤波的防护方法.论文确定了字符带宽、图像可读性等对于数字滤波的约束条件,采用FIR设计了相应的数字滤波器,应用数字滤波器和模拟滤波器的组合滤波,消除了数字滤波器所固有的插入损耗周期性波动的缺点,最后通过试验验证了分析结果,获得了一些具有重要应用价值的结论.     

基于FPGA的直接型FIR滤波器实现

FIR滤波器在数字通信系统中被大量使用,对其进行研究具有重要的意义。先对3种基本结构的FIR滤波器进行研究,说明直接型FIR滤波器使用的存储单元最少。接着给出了直接型FIR滤波器的实现原理框图,并分别对ROM单元和MAC单元模块所采用的实现方法占用存储单元和时钟频率进行具体比较,得出较优的直接型FIR滤波器的FPGA实现方案和框图。最后通过仿真验证了各模块的功能。此实现方案具有比较高的设计效率和推广应用价值。     

Efficient bit-level systolic array implementation of FIR and IIRdigital filters

Bit-level systolic architectures based on an inner-product computation scheme for finite-impulse response (FIR) and infinite-impulse-response (IIR) digital are presented. The FIR filter structure is optimized in the sense that for a given clock rate, both the utilization efficiency and average throughput are maximized. The IIR filter structure has approximately the same utilization efficiency and throughput rate as previous related techniques for processing a single data stream (channel), but it allows two data streams to be processed concurrently to double the performance. This feature makes the IIR system attractive for use in applications where multiple filtering and particularly bandpass analysis are required     

Realization of quick-look imaging for spaceborne SAR based on parallel processing

Large range cell migration is a severe challenge to imaging algorithm for spaceborne SAR. Based on design of Finite Impulse Response (FIR) filter and Range Doppler (RD) algorithm,a realization of quicklook imaging for large range cell migration is proposed. It realized quick-look imaging of 8 times reduced resolution with parallel processing on memory shared 8 CPU SGI server. According to simulation experiment, this quick-look imaging algorithm with parallel processing can image 16384x16384 SAR raw data within 6 seconds. It reaches the requirement of real-time imaging.     

Chromatic Dispersion Compensation Using Digital IIR Filtering With Coherent Detection

Digital infinite impulse response (IIR) filtering is proposed as a means for compensating chromatic dispersion in homodyne-detected optical transmission systems with subsequent digital signal processing. Compared to finite impulse response (FIR) filtering, IIR filtering achieves dispersion compensation (DC) using a significantly smaller number of taps. DC of 80 and 160 km in a 10-Gb/s binary phase-shift-keying is experimentally compared for the two filtering schemes. IIR filtering can achieve performance similar to the FIR filtering scheme.     

基于椭圆球面波函数的数字带通滤波器设计

为设计频谱性能优良的有限冲激响应( FIR)数字带通滤波器,从窗函数的性质及选择指标出发,分析了椭圆球面波函数( PSWF)作为窗函数的优势;在此基础上根据数字滤波器设计的原理和要求,选择0阶基带椭圆球面波函数作为窗函数设计数字带通滤波器,并利用微分方程状态转移矩阵逼近的PSWF求解算法,给出了基于PSWF的FIR数字带通滤波器设计方法。理论分析和仿真结果表明：PSWF数字带通滤波器具有较低的设计复杂度,与Kaiser滤波器和Blackman滤波器相比,其旁瓣衰减有超过7 dB的优势,且具有与两种滤波器相当的通带波纹波动和过渡带宽。