Design of new selective CIC filter functions with passband‐droop compensation

Abstract

he main aim of this reported work was to design new selective cascadedintegrator-comb (CIC) filter functions. The theoretical design equations and impulse response coefficients, as well as the frequency response characteristics of the novel filter functions are presented. Compared with existing filter functions in the literature, the proposed functions not only have improved insertion loss but also a multiplierless architecture, better passband characteristics and lower impulse response coefficients.

Coefficient quantization effects on new filters based on Chebyshev fourth-kind polynomials

“…The passband droop can be further improved by applying an additional filter, called compensating filter or compensator. This idea for improving the passband is given and applied on some other filters (comb, CIC and new CIC filters) like it is shown in [4] and [9]- [17]. Investigation can be done in order to elaborate which suggested method is the most convenient for passband droop compensation in these suggested filters.…”

“…Till now, researchers have suggested different methods for improving the digital filter efficiency as presented in [1]- [8]. Different methods presented in [4]- [8] share the same idea, namely, using CIC (Cascade-Integrator-Comb) sections with some added solutions to improve filter attenuation. Different methods are proposed to compensate for the passband droop as it is described in [9]- [17].…”

Optimum multiplierless compensators for sharpened cascaded‐integrator‐comb decimation filters

“…Introduction: Multiplierless decimation filters are used as building blocks in high-speed multirate systems. Various methods for their design have been considered, resulting in the cascaded-integrator-comb (CIC) filter [1], sharpened CIC (SCIC) filters [2,3], and several filters obtained by modification of the original CIC response [4][5][6][7]. All filters referred to introduce passband droop, which is especially high for SCIC filters utilising folding-band sharpening.…”

“…However, the proposed compensator with L = 3 and B = 3 ensures similar deviation by employing one adder less. It has the coefficients ĉ= [2 6 , 1-2 4 ]. In [11], the CIC compensator with five coefficients exhibits the deviation of 0.11 dB by using ten adders.…”

“…It is expected since the compensators in [12] were obtained by using the maximally flat error criterion and without the control of complexity. Finally, let us illustrate the compensation of the CIC-based FIR decimation filter proposed in [4]. In this case, H C (ω) in (4) denotes the passband response of used CIC-based filter, rather than the response of an SCIC filter.…”