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Durai Saravanan, V. Jayaprakasan " This paper presents a double sharpened CIC decimation filter, which consists of generalized comb filter as first stage, sharpened comb filter as second and third stage. The comb decimation filter at the first stage operates at the input sampling rate, sharpened second stage operates at lower samplin The comb decimation filter at the first stage operates at the input sampling rate, sharpened second stage operates at lower sampling rate as compared to first stage and sharpened third stage operates at lower than the first and second stages.
This reduces the sampling at every stage of the three stage CIC decimation filter. The sharpened second stage produces the narrow passband droop and better stop band alias rejection. This narrow passband droop will be compensated with the help of third stage which is sharpened section. Device utilization and simulation results are tabulated.
Abstract—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 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. Mitra " This paper presents a new multistage comb-rotated sinc RS decimator. The proposed structure consists of different cascaded comb sections, each down-sampled by a specific down-sampling factor.
The number of sections depends on the decimation factor of the original comb decimator. The first section The first section is realized in a non-recursive form. Using the polyphase decomposition, the sub-filters of the first section can be operated at lower rate which depends on the down-sampling factor of the first section.
Additionally, the rotated sinc RS filter is cascaded in the second section, thus permitting both multipliers of the RS filter to work at the lower rate. The magnitude response of the proposed structure is better than that of the original comb decimator.
Figure 1: CIC decimation filter The above decimation filter is attractive in many applications because of its very low complexity. It should be noted that while the differentiator section operates at the lower data rate, the integrator section works at the higher input data rate resulting in a larger chip area and a higher power consumption especially when the decimation factor and the filter order are high .
The use of a non-recursive equivalent to Eq. More details on a comparison of the performances of the recursive and non-recursive implementation are given in . In this paper we propose a new multistage structure in which the first stage is implemented non-recursively while all other stages are implemented recursively. The magnitude response of this structure is improved over that of the original comb filter by using a modified rotated sinc RS filter introduced in .
Unlike the structure advanced in , where one multiplier works at the high input rate, in the structure proposed in this paper, both multipliers work at the lower rate. Show Context Citation Context The decimation filter is the keyscomponent required to provide an efficient all-digitalssub-band tuner systems .
Yeung, S. This paper proposes to reduce the decimation factor of the multistage decimator so that its output can be fed directly to the Farrow structure for sample rate conversion, eliminating the need for another L-band filter for upsampling.
Furthermore, it was found out that the programmable FIR filter can Furthermore, it was found out that the programmable FIR filter can be replaced by a half-band filter placed immediately after the Farrow structure, i.
This significantly reduces the complexity of the proposed software radio receiver because this half-band filter, which consists of fixed filter coefficients, can be implemented efficiently without multiplication using SOPOT coefficients. As the coefficients of the multistage decimators and the subfilters in the Farrow structure are also fixed, they can also be implemented efficiently using the SOPOT coefficients.
As a result, apart from the limited number of multipliers required in the Farrow structure, the entire digital IF can be implemented without any multiplication. Design example is given to demonstrate the effectiveness and feasibility of the proposed approach.
In addition, it is usually assumed that thesprogrammable FIR and the SRC immediately after it are fastsenough to handle the decimated input signal. One drawback of thissconventional structure is tha The idea of software radio SWR implies the capability of changing the air-interface just by down-loading the respective software. Since analog components e. In such receivers the task of sample rate conversion SRC is essential and has to be performed in an adaptable manner.
Polynomial filters are a very suitable choice for sample rate conversion. Since the support length of the filter determines the effort and costs implementing this filter, minimizing the support is an important task.
It will be shown that using a more general approach to interpolation leads to filters with minimal support for a given accuracy. This results in a considerable reduction of the effort. 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, 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.
Gerez, Cornelis H. Slump " The use of mobile telephony has shown a spectacular growth in the last 10 years. A side effect of this rapid growth is an excess of mobile system standards. Therefore, the SDR concept is emerging as a potential pragmatic solution. It aims to build flexible radio systems, which are multipleservice, multi-standard, multi-band, re-configurable and reprogrammable, by software.
First, this paper presents a global overview of SDR. Furthermore, it explains the implementation of an SDR transmitter and receiver that have been simplified for the purpose of illustration. The correctness of the implemented system has been verified and measurements of the bit error rate versus the bit-energyto-noise-energy ratio are reported.
These special filters are cascaded integrated comb CIC filters. CIC filters can only be used in the first steps of the decimation process because the frequency response is bad. An example is shown in Figure 6. CIC filters require only additions and subtractions This paper introduces a new multistage CIC decimation filter based on non recursive and modified recursive structure of CIC filter. The resulting decimation filter has an improved magnitude response compared with that of a corresponding conventional CIC filter.
Additionally the filter is a multiplie Additionally the filter is a multiplierfree and has no filtering at high input rate. The sharpening technique is used to further improve the magnitude characteristic of the proposed structure. Dufferent method have been proposed to improve the magnitude characteristic of Eq.
The paper is organized as follows. Next section describes the linearly tapered C A commonly used decimation filter is the cascaded- integrator-comb CIC filter, which consists of two main sections: an integrator and a comb, separated by a down-sampler. This ffilter is attractive in many applications because of its very low complexity which requires no multipliers and storages.
The magnitude characteristic of this filter has a low attenuation in the stopband, and a droop in the desired passband, that is dependent upon the decimation factor M and the cascade size K. Additionally the integrator section works at the high input rate.
In this paper we present a new decimation filter based on cosine filters. The proposed structure is a multiplier-free and has an improved magnitude response compared with that of the corresponding conventional CIC filter.
Additionally there is no filtering at the high input rate. This paper presents the novel comb decimator. The method is based on the pass band comb compensation and the sharpening technique. The compensator is the simple multiplier less filter which can be moved to a lower rate which is M times less than the high input rate where M is the decimation factor.
The parameters of compensator are independent of the decimation factor. The resulting filter is the multiplier less filter and exhibits the significantly decreased pass band droop, as well as the increased attenuation in the folding bands, compared with the corresponding comb filter.
Application of filter sharpening to cascaded integrator-comb decimation filters
Owing to their reduced computational complexity, research on comb filters to date has been focused on 1 improving the magnitude characteristic, 2 preserving linearity of phase, and 3 having the least possible increase of computational complexity [ 2 — 24 ]. With this background, let us review the literature in these three categories. From the representative sample of works improving the magnitude characteristics of comb filters, we observe that the rotated-comb-based schemes [ 2 — 7 ] have the disadvantage of being susceptible to imperfect pole-zero cancelation. An effective way to prevent this problem consists in designing nonrecursive filters [ 3 , 4 , 7 ] with filtering implemented in polyphase form for ensuring power savings.
APPLICATION OF FILTER SHARPENING TO CASCADED INTEGRATOR-COMB DECIMATION FILTERS PDF
Dizil Proposed Sharpened Compensated Comb Filters Let us consider as subfilter the simplest compensated comb filter, which has the following transfer function [ 11 ]: Obviously, this is a preliminary estimation that depends on the accuracy of the formula being used. This paper proposed an optimization framework to design sharpening polynomials specifically suited to comb-based decimation filtering. Saramaki T, Ritoniemi T. An economical class of digital filters for decimation and interpolation. However, we must have monotonic magnitude characteristic over the passband region of the filter to be sharpened. Application of filter sharpening to cascaded integrator-comb decimation filters The main motive of this paper is to design a Sharpened decimation filter based on filterrs technique  with all the integrated advantages of existing scheme in order to achieve the better frequency response in pass-band as well as stop-band as compared to existing CIC structures for decimation. Citations Publications citing this paper.
Optimal Sharpening of Compensated Comb Decimation Filters: Analysis and Design
Willson, Jr. It combines the cascaded integrator-comb CIC multirate? This allows the? Furthermore, the use of? The resulting architecture is well suited for single-chip VLSI implementation with very high data-sample rates. Applications include all-digital subband tuning for wideband communication links and signal analysis. Block diagram of an all-digital subband tuner.