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Dr. Gordana Jovanovic Dolecek publishes as sole author a new algorithm in the journal with an IF impact factor: 15,204

In number 2 of the IEEE Signal Processing Magazine, which has an IF impact factor: 15.204,  was published an article in which Dr. Gordana Jovanovic Dolecek, researcher at INAOE, is the only author ( G. Jovanovic Dolecek, ”Update on the CIC multistage decimation filter with a minimum number of additions per output sample (APOS): Can we still decrease the number of APOS? Tips and Tricks", IEEE Signal Processing Magazine, vol.40, No. 2, 27 February 2023, pp.151-172, DOI: 10.1109/MSP.2022.3216720.)

This work investigates an efficient design of decimation filters important for downsampling in digital signal processing and digital communications.

This investigation explores some tips and tricks on how to decrease the number of additions per output sample (APOS) in a cascading combined integrator (CIC) multistage decimation filter, ensuring the lowest number of APOS for a given decimation factor, the desired minimum worst-case attenuation (WCA) in dB and the desired passband edge frequency.

The decimation factor is assumed to be a product of prime factors.

A modification of the multi-stage CIC decimation structure recently published in the literature was proposed. The structure provides the minimum number of APOS obtained by optimization for a given decimation factor, worst-case attenuation, and passband edge frequency. It was observed that it is possible to modify only the last stage of this structure, to obtain a smaller number of APOS.

Two cases are investigated depending on whether the decimation factor of the last stage is equal to two. In both cases, tips and tricks are presented to reduce the number of APOS.

In the first case, as a difference with respect to the original structure, the combs decimated by two are presented in recursive and non-recursive form. The integrators of the recursive combs are canceled in that phase, while the combs of the recursive combs are shifted at a lower rate. As a result, the number of APOS decreases. Furthermore, by applying polyphase decomposition to the non-recursive comb, the number of APOS decreases further, since the polyphase components are shifted after decimation by two.

In the second case, where the decimation in the last stage differs from the two, the comb in the last stage is also presented in non-recursive and recursive form. Unlike case 1, the combs in non-recursive form always have the order of two. As a result, polyphase decomposition can be used with the simple polyphase components applied to the non-recursive combs, decreasing the original number of APOS.

Finally, the proposed structure and the original optimal polyphasic structure are compared for different values of decimation factors and WCA in order to demonstrate the advantages of the proposed method.