Coefficients of maximally flat low and high pass nonrecursive digital filters with specified cutoff frequency

A simple and general method is presented for determining the coefficients of a lowpass or highpass maximally flat nonrecursive digital filter with a specified cutoff frequency.     

Further results on maximally flat nonrecursive digital filters

Starting with the Krawtchouk series representation of maximally flat FIR lowpass filters, a class of monotone bandpass filters is derived and exact design formulas are given.     

Explicit formula for filter function of maximally flat nonrecursive digital filters

A general formula for the filter function of maximally flat f.i.r. digital filters using modified Krawtchouk polynomials is presented. This formula permits a direct calculation of the filter weights. It is especially advantageous for either high or low passband/stopband width ratios.     

Maximally flat nonrecursive digital filters

In a recent letter, coefficients for a maximally flat nonrecursive transfer function were obtained via a special solution to the Hermite interpolation formula. This letter, however, shows how these coefficients can also be obtained by a simple `classical? method that sets derivatives of a rational function to zero.     

Explicit formulas for the weighting coefficients of maximally flat nonrecursive digital filters

An explicit formula is given for the weighting coefficients of maximally flat nonrecursive digital filters based on Miller's [1] design. A scheme is also presented for evaluating these coefficients with the minimum possible computation.     

Two-dimensional FIR digital filters with maximally flat magnitude

Generation of a class of maximally flat magnitude two-dimensional FIR functions employing McClellan transformation is described and their properties are discussed.     

Explicit formulas for coefficients of maximally flat FIRlow/highpass digital filters

New designs of general low/high pass MAXFLAT filters are derived from an available design of halfband lowpass MAXFLAT filters, using a new relationship developed between the tap-coefficients of general and halfband lowpass filters. The presented designs have explicit tap-coefficients formulas, are extremely simple and exactly meet the desired cutoff frequency     

Design of nonrecursive digital moving-target-indicator radar filters

This letter describes the design methods for a class of non-recursive digital m.t.i. filters with a multiple zero at z = 1 and an equiripple passband. Some examples of these responses are given, together with the filter coefficients.     

变频长自适应数字滤波器的稳定条件

变步长自适应数字滤波器的权值随信号和噪声的变化自动调整时可能出现不稳定。为解决这一问题,本文提出变步长自适应数字滤波器的权值收敛条件,该条件具有较少保守性,对输入信号的统计特性没有严格限制,本文证明自适应数字滤波的稳定性可由其权值收敛条件确定。利用该权值收敛条件,可设计确保变步长自适应数字滤波器的稳定的变收敛因子。     

多相滤波数字信道化的FPGA实现

以多相滤波为基础,结合均匀滤波器组,采用50％重叠的子信道划分,提出了一种数字信道化实现方法,解决了高速实时处理与FPGA处理速度之间的矛盾,克服了信道化接收机的接收盲区.基于FPGA,提出了短波宽带数字信道化的设计思路和实现方法.仿真结果表明,该设计有较强的实用性和通用性.     

Sine-cosine squared-magnitude function for maximally flat digital bandpass filters with adjustable skirt selectivities

A sine-cosine squared-magnitude function for a digital bandpass filter is proposed. It offers a maximally flat passband magnitude response and more flexibility on the number of exchangeable zeros at ?T = 0 and ?T = ? rad.     

Design of nonrecursive digital filters with linear phase

A new class of selective nonrecursive digital filters with independently prescribed equiripple passband and stopband attenuation and linear phase is obtained by numerical solution of a set of nonlinear equations. Some examples are given, and a comparison is made of the new solutions and those previously known.     

Design of nonrecursive digital filters with minimum phase

A method is described of transforming nonrecursive filters with equal-ripple attenuation in the passband, stopband and linear phase into those with minimum phase and half the degree, but again with equal-ripple attenuation in the passband and stopband.     

Explicit formula for the coefficients of maximally flat nonrecursive digital filter transfer functions expressed in powers of cos w

An explicit formula for the coefficients of the transfer function of a maximally flat nonrecursive digital filter, expressed in powers of cos w, is derived by exploiting the properties of the Kaiser-Hamming [1] amplitude change function polynomial. Transfer functions expressed in this form are convenient for implementing variable cutoff filters [2].     

Design of maximally flat sharp cutoff low-pass filters

A method is given for obtaining the parameters of a maximally flat sharp cutoff low-pass filter with coincident multiple transmission zeros, which satisfies arbitrary passband and stopband specifications.     

Implementation of 2-D denominator-separable digital filters using first-order all-pass sections

It is established that denominator-separable transfer functions which characterize an important subclass of 2-D filters can be expressed as a linear combination of first-order (1-D or 2-D separable) all-pass transfer functions with real or complex coefficients. This type of expansion is referred to as all-pass expansion of the corresponding transfer function. Based on this all-pass expansion, we derive some efficient structures for the realization of 2-D denominator-separable filters using all-pass sections.On leave from S.V. University College of Engineering. Tirupati-517502, India.     

Equalization problems in a digital FM receiver

In some recent papers a new all-digital intermediate frequency unit for the application in commercial broadcast FM receivers was introduced. Serious problems of an efficient hardware solution are the dynamic requirements of the input analog-to-digital converters, which can be solved by narrow-band analog pre-filtering, only. In this paper a digital nonrecursive equalization network is described, which can be used to compensate the non-ideal characteristics of the analog pre-filters. Furthermore, it will be shown that this equalization technique can be applied to multipath echo cancellation, as well. Some examples will be given to illustrate the reduction of nonlinear distortions after demodulation, if digital equalization is carried out.     

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.     

Insertion loss function synthesis of maximally flat parallel-coupled line bandpass filters

Insertion loss (IL) functions are derived for synthesis of microstrip parallel-coupled line bandpass filters with maximally flat responses. The derivation is performed by successively multiplying the ABCD matrices of all coupled stages. Simultaneous equations for determining linewidth and line spacing of the coupled stages are established by total Q (Q/sub T/) of the filter specification and comparing the IL function with the canonical form. The results are provided for filters of order N/spl les/6. Two filters with fractional bandwidths /spl Delta/=30% are synthesized and demonstrated by simulation using a full-wave software package. In addition, two filters with /spl Delta/=40% and 50% are fabricated. Tapped line inputs are employed to these two circuits since some linewidths or gaps are beyond the fabrication resolution. The measured results show very good agreement with the theoretical responses.