212 research outputs found
Design of Multistage Decimation Filters Using Cyclotomic Polynomials: Optimization and Design Issues
This paper focuses on the design of multiplier-less decimation filters
suitable for oversampled digital signals. The aim is twofold. On one hand, it
proposes an optimization framework for the design of constituent decimation
filters in a general multistage decimation architecture. The basic building
blocks embedded in the proposed filters belong, for a simple reason, to the
class of cyclotomic polynomials (CPs): the first 104 CPs have a z-transfer
function whose coefficients are simply {-1,0,+1}. On the other hand, the paper
provides a bunch of useful techniques, most of which stemming from some key
properties of CPs, for designing the proposed filters in a variety of
architectures. Both recursive and non-recursive architectures are discussed by
focusing on a specific decimation filter obtained as a result of the
optimization algorithm.
Design guidelines are provided with the aim to simplify the design of the
constituent decimation filters in the multistage chain.Comment: Submitted to CAS-I, July 07; 11 pages, 5 figures, 3 table
VLSI Implementation of Cascaded Integrator Comb Filters for DSP Applications
The recursive comb filters or Cascaded Integrator Comb filter (CIC) are commonly used as decimators for the sigma delta modulators. This paper presents the VLSI implementation, analysis and design of high speed CIC filters which are based on a low-pass filter. These filters are used in the signal decimation which has the effect on reducing the sampling rate. It is also chosen because its attractive property of both low power and low complexity since it dose not required a multiplier. Simulink toolbox available in Matlab software which is used to simulator and Verilog HDL coding help to verify the functionality of the CIC filters. Design procedures and examples are given for CIC filter with emphasis on frequency response, transfer function and register width. The implementation results show using Modified Carry Look-ahead Adder for summation and also apply pipelined filter structure enhanced high speed and make it more compatible for DSP applications
On the Polyphase Decomposition for Design of Generalized Comb Decimation Filters
Generalized comb filters (GCFs) are efficient anti-aliasing decimation
filters with improved selectivity and quantization noise (QN) rejection
performance around the so called folding bands with respect to classical comb
filters.
In this paper, we address the design of GCF filters by proposing an efficient
partial polyphase architecture with the aim to reduce the data rate as much as
possible after the Sigma-Delta A/D conversion. We propose a mathematical
framework in order to completely characterize the dependence of the frequency
response of GCFs on the quantization of the multipliers embedded in the
proposed filter architecture. This analysis paves the way to the design of
multiplier-less decimation architectures.
We also derive the impulse response of a sample 3rd order GCF filter used as
a reference scheme throughout the paper.Comment: Submitted to IEEE TCAS-I, February 2007; 11 double-column pages, 9
figures, 1 tabl
Optimal Sharpening of Compensated Comb Decimation Filters: Analysis and Design
Comb filters are a class of low-complexity filters especially useful for multistage decimation processes. However, the magnitude response of comb filters presents a droop in the passband region and low stopband attenuation, which is undesirable in many applications. In this work, it is shown that, for stringent magnitude specifications, sharpening compensated comb filters requires a lower-degree sharpening polynomial compared to sharpening comb filters without compensation, resulting in a solution with lower computational complexity. Using a simple three-addition compensator and an optimization-based derivation of sharpening polynomials, we introduce an effective low-complexity filtering scheme. Design examples are presented in order to show the performance improvement in terms of passband distortion and selectivity compared to other methods based on the traditional Kaiser-Hamming sharpening and the Chebyshev sharpening techniques recently introduced in the literature
COEFFICIENT QUANTIZATION EFFECTS ON NEW FILTERS BASED ON CHEBYSHEV FOURTH-KIND POLYNOMIALS
The aim of this paper is to construct non-recursive filters, extensively used type of digital filters in digital signal processing applications, based on Chebyshev orthogonal polynomials. The paper proposes the use of the fourth-kind Chebyshev polynomials as functions in generating new filters. In this kind, low-pass filters with linear phase responses are obtained. Comprenhansive study of the frequency response characteristics of the generated filter functions is presented. The effects of coefficient quantization as one type of quantization that influences a filter characteristic are investigated here also. The quantized-coefficient errors are considered based on the number of bits and the implementation algorithm
Merenje komponenti električne snage po standardu IEEE 1459-2010
Merenje u nesinusoidalnim uslovima je u centru istraživanja i mnogo se napora ulaže da se pojam reaktivne snage star više od sedamdeset godina definiše na nov način. Postoji niz pristupa rešavanju problema definisanja snaga i/ili pokušaja koncipiranja merne instrumentacije za merenje snaga u sistemima naizmenične struje pod nesinusoidalnim uslovima. Jedini standard koji se odnosi na specifične zahteve za tačnost i odgovarajuće uslove testiranja u prisustvu harmonijskih izobličenja je IEEE Std. 1459-2010, koji ne daje definiciju reaktivne snage u nesinusoidalnim uslovima. Koncept ovog IEEE standarda je baziran na raz-dvajanju snage na fundamentalni i nefundamentalni deo. U literaturi su prisutne različite tehnike za imple-mentaciju standarda IEEE Std. 1459-2010. Ovaj standard je implementiran pomoću dva osnovna prilaza: (1) dvostepeni algoritam sa estimacijom harmonijskih spektara naponskog i strujnog signala u prvom koraku i računanjem nepoznatih komponenti snage u drugom koraku i (2) filterska implementacija kombinovana sa Clarke-Park transformacijom u slučaju trofaznog sistema. U radu je prikazana nova metoda za merenje električnih veličina definisanih standardom IEEE 1459-2010 koristeći drugi pristup. Ključni elementi su adaptivni pojasni i niskopropusni FIR filteri koji izdvajaju fundamentalnu i jednosmernu komponentu. U radu su korišćene tehnike oversemplinga i decimacionih filtera, čime se izbegavaju problemi vezani za osetljivost na zaokruživanje koeficijenata FIR kaskadnih filtera velikog reda, smanjuje obim numeričkih računanja i povećava tačnost merenja. Estimacija simetričnih komponenti vrši se pomoću matrice adaptivnih faznih korektora. U cilju procene performansi algoritma izvršene su računarske simulacije i dati njihovi rezultati.In this paper, the design and implementation of a novel recursive method for the power measurement ac-cording to the IEEE Standard 1459-2010 have been described. The most important parts are adaptive band and low-pass FIR filters that extract fundamental and dc components, respectively. In addition, by using oversampling techniques and decimation filters, coefficient sensitivity problems of the large-order FIR comb cascade structure are overridden and the parameter estimation accuracy is improved. The symmetrical components are estimated through a transformation matrix of adaptive phase shifters. The effectiveness of the proposed techniques is demonstrated by simulation results
Third order CMOS decimator design for sigma delta modulators
A third order Cascaded Integrated Comb (CIC) filter has been designed in 0.5μm n-well CMOS process to interface with a second order oversampling sigma-delta ADC modulator. The modulator was designed earlier in 0.5μm technology. The CIC filter is designed to operate with 0 to 5V supply voltages. The modulator is operated with ±2.5V supply voltage and a fixed oversampling ratio of 64. The CIC filter designed includes integrator, differentiator blocks and a dedicated clock divider circuit, which divides the input clock by 64. The CIC filter is designed to work with an ADC that operates at a maximum oversampling clock frequency of up to 25 MHz and with baseband signal bandwidth of up to 800 kHz. The design and performance of the CIC filter fabricated has been discussed
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