一种设计IIR数字滤波器的参数化方法

 基于连续时间状态空间结构和广义双线性变换,提出了一种设计无限冲激响应(IIR)数字滤波器的参数化方法.优点是稳定区域包含了整个参数空间,因此可以采用无约束优化方法.给出了仿真实例,并与已有的设计方法进行了比较,其通带波动、阻带衰减、群迟延等性能更为优越.     

Q value analysis of microwave photonic filters

This paper first presents the fundamental principles of the microwave photonic filters.As an example to explain how to implement a microwave photonic filter, a specific finite impulse response (FIR) filter is illustrated.Next, the Q value of the microwave photonic filters is analyzed theoretically, and methods around how to gain high Q value are discussed.Then,divided into FIR filter, first-order infinite impulse response (IIR) filter, and multi-order IIR filter, several novel microwave photonic filters with high Q value are listed and compared.The technical difficulties to get high Q value in first-order IIR filter and multi-order IIR filter are analyzed concretely.Finally, in order to gain higher Q value, a multi-order IIR microwave photonic filter that easily extends its order is presented and discussed.     

快速傅立叶变换辅助设计数字低通滤波器

详尽讨论了快速傅立叶变换(FFT)应用于有限冲击响应(FIR)数字低通滤波器(DLPF)的设计和分析方法.应用FFT算法,将理想DLPF幅频特性转换到变换域,获得其变换域序列;设计窗函数对该序列开窗,获得FIR有限序列;应用快速傅立叶逆变换(IFFT)对其进行变换,获得相应窗函数可实现DLPF幅频特性.结果发现,FFT算法可获得与传统卷积算法相同的结果;不需要推算窗函数的频谱解析表达式;可以处理Kaiser窗等变换域解析式复杂、频域解析式难以精确求解的窗函数设计与分析.与传统的卷积分析法相比,FFT不仅算法简单、灵活,而且处理能力强,是分析FIR DLPF设计的有力工具.     

数字滤波器在语音信号处理中的应用

针对语音信号去噪的问题,设计了各种类型的IIR数字滤波器,然后用不同类型的滤波器处理不同的噪声,这改变了传统的一成不变的去噪方式.实验结果表明,同样的噪声用不同的滤波器处理,效果各有不同,经过分析,选出最优的滤波方式.     

超低频通信中海洋补偿滤波器设计

分析了超低频接收机中海洋补偿滤波器的作用,分别采用1零点1极点、2零点1极点无限脉冲响应滤波器设计超低频海洋补偿滤波器,零点和极点通过数值计算得到。分析结果表明:在20～200Hz频段内,实现的滤波器可以很好地逼近理论的海洋补偿滤波器;在0～130m范围内,实现的2零点1极点滤波器可以将幅度响应误差控制在1 dB左右,能满足超低频接收机的设计要求。     

介质膜滤波器色散特性的数值方法

文章根据介质膜滤波器为最小相位滤波器的特点,提出了一种从介质膜滤波器的幅度响应重构出相位响应,然后求出它的群速度延迟以及色散的数值方法.最后,实验验证了理论计算结果.     

DFT域全相位数字滤波器的设计与实现

本文给出了一种带双窗的频域全相位数字滤波器结构,经过理推导得到与其等效三种实现形式。对系统特性的分析结果表明,双窗全相位数字滤波器在通带和阻带内的波纹基本消除并且可以方便地设计各种滤波器;最后通过仿真实验,验证了理论推导的正确性和全相位数字滤波器的实用性。     

支持任意系数长度和数据类型的FIR滤波器向量化方法

 向量处理器的向量化算法映射是难点问题.提出一种支持任意系数长度和数据类型的FIR滤波器向量化方法,将(Finite Impulse Response)滤波器的卷积计算划分为系数长度步向量乘法和加法计算,每一步的向量乘法和加法计算在各个向量处理单元上并行执行,计算一个输出结果的所有乘法和加法计算都在同一向量处理单元上完成,每次循环能够同时完成向量处理单元数量个输出结果的计算.在向量处理器YHFT-Matrix的实验结果表明,该向量化FIR滤波器能够取得高效的计算性能和加速比.     

FIR数字滤波在MEMS加速度计中的应用

简要分析了MEMS加速度计应用模型中的噪声来源,介绍了FIR数字低通滤波器的设计方法,并用FPGA实现的FIR滤波器对MEMS加速度计的输出信号进行了实时滤波处理。通过对滤波前后时、频域信号的比较,可以看出采用FIR数字低通滤波器能有效抑制加速度计输出信号中的高频噪声、提高加速度计的测量精度。实验结果表明,滤波前噪声信号标准偏差为1.53×10-5V,经FIR数字低通滤波后的噪声信号标准偏差降低为5.4×10-6V,加速度计的分辨率由126μg提高到42μg。     

针对级联型ⅡR滤波器群延时的均衡优化技术

为了减小由非恒定群延时所引起的滤波器的输出信号失真,本文提出一种适用于级联型无限长脉冲响应数字滤波器的群延时均衡优化方法.通过在级联型ⅡR数字滤波器每一级的输出插入全通均衡器,减小群延时在通带范围内的变化,进而减小滤波器的输出信号失真.对于本文提出的群延时优化方法,当采用1阶和2阶均衡器进行电路优化时,在0~100Hz的通带范围内,分别将群延时的变化量减小了28.19%和49.93%.基于0.18μm CMOS标准单元库进行逻辑综合与版图设计,最终得到整个滤波电路IP核版图的面积为0.1747mm².相比于已有文献方法,本文方法在群延时优化上效果显著,电路实现上功耗和面积较小,非常适合片上系统应用.     

QDPSK信号数字化解调器中带通滤波器的设计与仿真

经过限带滤波后的QDPSK信号的码元波形可分为稳定区与过渡区，根据这一特点可以利用DFT方法来实现信号的解调和位同步。在这种数字化解调器中需要设计一个合适的带通滤波器，以便尽可能地消除信号的旁瓣分量而不影响信号码元稳定区内的波形。本文介绍了上述带通滤波器的方案选择和基于Matlab的滤波器参数设计方法，以及仿真效果。     

直扩系统中IIR格型滤波器抑制窄带干扰新方法与性能分析

该文提出一种直扩系统中基于IIR格型陷波器时域频域相结合的窄带干扰抑制新方法,该方法采用时域频域并行处理的结构,通过最优加窗和频谱校正技术在频域精确估计出干扰信号的频率,根据频率估计误差和干信比求出最优陷波带宽,由此自适应地调整时域IIR格型陷波器的参数。分析和实验表明,该方法较传统的自适应IIR窄带干扰抑制方法不仅具有更高的稳定性和实时性,而且在干扰得到有效抑制的情况下使有用信号的损失达到最小。     

A New Architecture of Matched Filter for Chirp Spread Spectrum in IEEE 802.15.4a

We propose a new matched filter architecture for chirp spread spectrum in IEEE 802.15.4a. By using relations among the four subchirps, the proposed architecture comprises four subfilters utilizing only a set of coefficients matched to the first subchirp. The four subfilters share adders and registers, and as a result, the required adders and registers for implementation are reduced.     

基于GC4016的SDR数字中频接收机滤波器的设计与实现

中频数字化是软件无线电(SDR)系统设计中的一项关键技术。从射频、基带与中频的制约关系出发,结合Graychip公司生产的多通道数字下变频器GC4016芯片,给出了中频数字滤波器的设计方法,从理论上进行了分析和仿真,并在实际工程中进行了实验验证,得到了预期的结果。     

用于DWDM的一类光子晶体滤波器

用转移矩阵法模拟计算了通过2组不同禁带的光子晶体级联构成的窄带滤波器的光学特性，设计了信道间隔为0．80nm和0．08nm的密集波分复用（DWDM）光子晶体滤波器。模拟结果表明，这种滤波器的透射特性几乎不受滤波器两边折射率的影响，既可生长在光纤的一端，也可植入光纤内部，还可直接在空气环境中使用，使滤波系统简单、轻便。     

数字滤波技术在气相紫外光电子能谱仪数据采集中的应用

为既能广泛用于稳定分子的研究又能用于瞬变物种研究的气相紫外光电子能谱仪设计了数据采集系统，应用Windows支持下的Visual C 6．0编程技术，编制了具有友好界面、操作简便的数据采集系统软件．数据采集系统利用Butterworth低通数字滤波器对采集到的数据进行处理，来消除高频的噪声提高信噪比．     

FPGA realization of FIR filters for high-speed and medium-speed by using modified distributed arithmetic architectures

This paper presents the design optimization of fully pipelined architectures for area-time-power-efficient implementation of finite impulse response (FIR) filter. The architectures are designed to obtain a suitable area-time tradeoff. Analysis of the performance of different filter orders and different address lengths of partial tables indicate the choice of four input partial tables presents the best of area-time-power-efficient realizations of FIR filter compared with the existing LUT-less DA-based implementations of FIR filters in both high-speed and medium-speed. Moreover, a number of further experiments not only shows the pipeline register’s significant influence to the maximum frequency of the FIR filters but also indicates it also has area usage. Final experiment shows that with the help of using pipeline register, the choice of 4-bits-per-clock (4BPC) of the architecture for word-length N=8 with four input partial table yields the best cost-effective when comparing with other different cases in both high-speed and medium-speed implementations.     

Design of FIR filter ISOTA with the aid of genetic algorithm

The field of digital signal processing has been receiving justified attention over the years because of a number of reasons including sophisticated algorithms, high computational speed and wider area of applications. In connection to this, design of finite impulse response (FIR) filter has drawn the attention of researchers throughout the globe. A number of promising developments has been carried out over the last few decades which emphasize on the design of hardware efficient filter structure. In this paper, a new technique of FIR filter design has been addressed by virtue of genetic algorithm. Filter coefficients have been searched over the discrete space in such a way that the architecture consists of shifts and only two adders. As a matter of fact, the proposed FIR filter involving shift and only two additions (ISOTA) results in minimal hardware cost during its implementation. This has been illustrated by means of a few example filters in this work. Some of the recently proposed FIR ISOTA filters have also been taken for the purpose of comparison. Finally, the proposed filter has been implemented on Altera Cyclone IV FPGA board.     

An unbiased p-step predictive FIR filter for a class of noise-free discrete-time models with independently observed states

The paper addresses a new unbiased p-step toward predictive finite impulse response (FIR) filter for a class of discrete-time deterministic state space models, which states are represented on a horizon of N past points with degree polynomials and observed independently. It is implied that measurements are not available at a current time point n. The problem arises in synchronization and tracking when a signal is lost. Generic coefficients are derived via the Bernoulli polynomials for a two-parameter family of the polynomial filter gains. A generalization is provided for the linear (ramp) and quadratic filter gains. We show that the solution proposed is efficient in applications to predictive filtering of the states of local clocks of digital communication network nodes when a synchronizing signal is temporarily not available.     

一类非线性时滞系统的鲁棒H∞滤波器设计

 研究了满足下列条件的时滞系统的鲁棒H_∞滤波问题:假设系统的参数矩阵带有不确定性,且不确定参数是时变且范数有界的.在系统的状态与输出中同时都含有非线性无穷分布时滞与离散时滞.在设计滤波器的过程中,引入了一个新的Lyapunov-Krasovskii泛函.通过线性矩阵不等式技术,提出了参数不确定时滞系统的鲁棒H_∞滤波器存在的时滞依赖条件.鲁棒H_∞滤波器可以保证带有参数不确定性的滤波误差系统是渐近稳定的,并且满足给定的H_∞性能指标.通过仿真的研究证明了该方法的有效性.