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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Section 6 highlights the characteristics to be considered for the sharpening of the second-stage filter in a two-stage comb-based architecture. Thus the second sharpened stage operates at lower sampling rate which is M1 times lower than the input sampling rate.

An effective way to prevent this problem consists in designing nonrecursive filters [ 347 ] with filtering implemented in polyphase form for ensuring power savings. Moreover, two-stage comb-based decimation schemes have gained great popularity because the comb decimation filter in the first stage, designed in nonrecursive form, can be implemented at lower rate by polyphase decomposition, thus resulting in lower power consumption.

On design of two-stage CIC compensation filter. The basic building blocks of a CIC filter are an integrator and a comb section. Note that K must be an even value to avoid fractional delays. Sharpening method by Kaiser and Hamming [12] gives the idea of filter sharpening by multistage use of the same filter. A family of sharpening filters Hnm f is given by.


Clearly, the proposed structure can have a lower computational complexity i. Saramaki T, Ritoniemi T. As Coleman pointed out in [ 22 ], these optimization resources could be inaccessible to many designers.

Optimal Sharpening of Compensated Comb Decimation Filters: Analysis and Design

However, the magnitude response of comb filters presents a droop in the passband region and low stopband attenuation, which is undesirable in many applications. From a practical point of view, decimation is usually accomplished using a cascade of two or more stages.

Figure 1 presents the proposed structure to efficiently implement a decimation filter in a CIC-like form.

Applocation Center Support Center. Very-large-scale integration Signal processing Throughput. This is done in order to achieve an equiripple passband deviation in the overall filter H TS z. Simple method for compensation of CIC decimation filter.

From This Paper Figures, tables, and topics from this paper. The implementation of second and third sharpened stage is shown in Fig.

The filter in the first integrrator-comb is a comb filter of order K decimating by a factor Mwith z -transfer function and zero-phase frequency response, respectively, given as.

For more rigorous analysis of the results, the pass-band as well as stop-band of Fig. This filter is identified by H a z.

It is interesting to note that, with the proposed sharpening approach, we can obtain an overall magnitude response attaining desired passband and stopband deviations by improving only the second-stage filter. The proposed sharpened filter produced much better improvement in pass-band droop and better alias rejection in stop-band than the existing conventional CIC filter [2] and modified sharpened CIC filter [11] for the same decimation factor.


The zero-phase frequency response is. However, generally speaking, sharpened compensated comb filters become effective as the passband and stopband specifications become more stringent. The simulation results also verify the design of proposed sharpened decimation filter. However, in methods [ 2324 ] the filter designer does not have control on the exact passband deviation and stopband attenuation achieved by the designed filter.

A high speed digital decimation filter with parallel cascaded integrator-comb pre-filters.

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

Assuming the group delay of H z to be D samples, where. The proposed filtering structure and the corresponding guidelines to decide when to use sharpened compensated filters instead of sharpened comb filters without decimatoon are introduced in Section 4.

In multistage implementation approach with K number of stages, the above transfer function can be represented as. Understanding Digital Signal Processing.

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