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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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
This allows the first-stage CIC decimation filter to be followed by a fixed-coefficient second-stage filter, rather than a programmable filter, thereby achieving a significant hardware reduction over existing approaches. Therefore this proposed filter design is best suited for DSP based applications where integratoor-comb best pass-band performance is required. But the decimation process leads to aliasing and imaging errors .
We notice in passing that a somewhat similar optimization approach was cascadwd 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.
Therefore the transfer function of proposed filter can be written as. Optimal Sharpening of CIC filters and an efficient implementation through Saramaki-Ritoniemi decimation filter structure. Non-recursive digital filter design using I 0 -sinh window function. The sharpened second and third stage leads to improvement in pass-band droop and better stop-band alias rejection.
Analog and Digital Signal Processing, Vol. 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.
An overview of decimator structures for efficient sigma-delta converters: Introduction Efficient decimation filtering for oversampled discrete-time signals is key in the development of low-power hardware platforms for reconfigurable communication transceivers [ 1 — 26 ].
Create fA and b eharpening 20 — In this case, the proposed sharpened decimation filter has shown much improvement in pass-band droop and a little improvement in stop-band alias rejection as compared to existing conventional CIC filter  and modified sharpened CIC filter . But the overall frequency response does not meet the design specification of various multirate systems.
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Obviously, this is a preliminary estimation that depends on the accuracy of the formula being used. Figure 1 presents the proposed structure to efficiently implement a decimation filter in a CIC-like form. 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.
Additionally, this structure has all the sharpening coefficients at lower rate and, when integer coefficients scaled by a power of two are used, an effective overall structure is obtained, which does not suffer from finite-precision effects as rotated-comb-based methods. The goal of the optimization problem was to minimize the min-max error over the frequency bands of interest of the sharpened filter. The complete structure can be implemented from eq.
Note that K must be an even value to avoid fractional delays.
Other approaches improve the passband with low-order compensators and stopband attenuation by either increasing the order of the comb filter [ 8 — 14 ] or exploiting additional filtering at high rate [ 15 — 17 ]. Clearly, the proposed structure can have a lower computational complexity i.
Using a simple three-addition compensator and an optimization-based derivation of sharpening polynomials, we introduce an effective low-complexity filtering scheme. Instead of sharpening all the comb stages, sharpening technique is applied to the last stage which provided very good results. Decimation signal processing Search for additional papers on this topic.
This filter sharpening technique is applied to CIC filters to reduce the pass-band droop and to improve stop-band attenuation in CIC filters. The main motive of this paper is to design a Sharpened decimation filter based on sharpening 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.
On the use of interpolated second-order polynomials for efficient filter design in programmable downconversion.
Application of filter sharpening to cascaded integrator-comb decimation filters – Semantic Scholar
The reasons at the very basis of this work stem from the following observations. With this setup, we have.
Nine digital filters for decimation and interpolation. Two-stage CIC-based deciamtion with improved characteristics. Finally, concluding remarks are presented in Section 8. This architecture achieves better resource utilization over existing approaches because in this structure the first stage CIC decimation filter is followed by a fixed-coefficient second-stage filter rather than a programmable-coefficient filter. The sharpening coefficients are guaranteed to be integers scaled by power-of-2 terms, thus resulting in low-complexity structures.
However, generally speaking, sharpened compensated comb filters become effective as the passband and stopband specifications become more stringent. Therefore, preserving a simple sharpening polynomial and improving the stopbands with the increase of Kas suggested in [ 23 ], do not guarantee a result with low computational complexity. This paper presents the design of Sharpened three stage CIC filter for decimation.
However, the work [ 34 ] does not provide any method to find optimal discrete coefficients and simple rounding has been applied to the infinite precision solution, making pointless the infinite-precision optimization. Comb filters are used in the interator-comb stage of the decimation chain because their system function is simple and it does not require any multiplier.