A new architecture for the implementation of high-order decimation filters is described. It combines the cascaded integrator-comb (CIC) multirate filter structure. Application of filter sharpening to cascaded integrator-comb decimation filters. Authors: Kwentus, A. Y.; Jiang, Zhongnong; Willson, A. N.. Publication. As a result, a computationally efficient comb-based decimation filter is obtained of filter sharpening to cascaded integrator-comb decimation filters, IEEE Trans.

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Obtain the sharpening coefficients p k using The goal of the optimization problem was to minimize the min-max error over the frequency bands of interest of the sharpened filter.

When this structure is chosen, the applicaiton comb filter must be carefully designed since this is the filter where the worst-case magnitude characteristic of the overall cascade does occur. Comb filters are a class of low-complexity filters especially useful for multistage decimation processes. We detail the optimization framework to design sharpened comb-based filters to attain given specifications on the acceptable maximum passband distortion and selectivity.

In addition, we have. For more rigorous analysis of the results, the pass-band as well as stop-band of Fig. Therefore the transfer function of proposed filter can be written as. Clearly, the filter designed with the proposed method presents both improvements: Therefore this proposed filter design is best suited for DSP based applications where the best pass-band performance is required.

In this paper, we propose to use the general sharpening polynomial from 5finding the coefficients through optimization. However, we must have monotonic magnitude characteristic over the passband region of the filter to be sharpened. Decimation signal processing Search for additional papers on this topic. The filter H a zimplemented with a CIC-like structure, requires 20 integrators working at high rate, due to its double-sharpening scheme.

However, the work [ 34 ] does not provide any method to appliation optimal discrete coefficients and simple rounding has been applied to the infinite precision czscaded, making pointless the infinite-precision optimization.


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 ].

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The following examples are discussed to show the improvement of magnitude characteristics of comb filters achieved with the proposed method in comparison to other sharpening-based schemes recently introduced in the literature. Two-stage CIC-based decimator with improved characteristics. The optimized sharpening coefficients are finite-precision values resulting in multiplierless structures, which are important for low-power applications.

Simple method for compensation of CIC decimation filter. In many modern digital systems, signals of different sampling rates have to be processed at the same time and such systems are commonly known as multirate system.

With this background, let us review the literature in these three categories. In two-stage comb-based decimation schemes, magnitude response improvements over the passband and the first folding band can be achieved by improving only the second-stage comb filter. An effective way to prevent this problem consists in designing nonrecursive filters [ 347 ] with filtering implemented in polyphase form for ensuring power savings.

Thus, cwscaded sharpening polynomial must meet the following simultaneous conditions:. Please review our privacy policy. We notice in passing that a somewhat similar optimization approach was derived by Candan and made available online at [ 34 ], along with an extensive MATLAB code that, in general terms, finds the infinite-precision coefficients using the linprog function.

Showing of 9 references. So, after replacing, the transfer function of sharpened CIC filter is given by eq.

The reason is that the increased complexity in the sharpened compensated comb structures amounts to only 3 extra additions per filtsrs degree when the compensator from [ 11 ] is usedand these additions work at lower rate.

Optimal Sharpening of Compensated Comb Decimation Filters: Analysis and Design

However, generally speaking, sharpened compensated comb filters become effective as the passband and stopband specifications become more stringent. Problem Motivation, Contributions, and Paper Organization The reasons at the very basis of this work stem from the following observations.


With this setup, we have. The sharpened second and third stage leads to improvement in pass-band droop and better stop-band alias rejection. From This Paper Figures, tables, and topics from this paper. The proposed decimation filter has Cascaded-Integrator Comb filter as first stage, Sharpened Cascaded-Integrator Comb filter as second and third stage.

Assuming the group delay of H z to be D samples, where. These cases are shown in Figure 2. The main motive of this paper is to design a Sharpened decimation filter based on sharpening technique [12] with all the integrated advantages of existing scheme in order to achieve the better frequency response in pass-band as applicatjon as stop-band as compared to existing CIC structures for decimation.

Received Aug 31; Accepted Oct Therefore, preserving a simple sharpening polynomial and improving the stopbands with filtee increase of Kas suggested in [ 23 ], do not guarantee a result with low computational complexity. A novel two-stage nonrecursive architecture for the design of fitler comb filters.

In this case, the proposed sharpened decimation filter has shown a little improvement in pass-band droop and stop-band alias rejection as compared to existing conventional CIC filter [2] and modified sharpened CIC filter [11].

Application of filter sharpening to cascaded integrator-comb decimation filters – Semantic Scholar

Further the third stage operates at M2 times the lower sampling rate than the second stage and the frequency response of second stage is further sharpened by third stage.

Accurate estimation of minimum filter length for optimum FIR digital filters. On the polyphase decomposition for design of generalized casscaded decimation filters. Hogenauer [2] introduced the CIC filter structure for economical design of decimation and interpolation filters.