Novel Multiplierless Wideband Comb Compensator with High Compensation Capability

Abstract

This paper proposes a novel multiplierless comb compensation filter, which has the absolute passband deviation less than 0.1dB in the wide passband. The compensator consists of a cascade of two simple filter sections, both operating at a low rate. The magnitude characteristics of the two component filters are synthesized as sinewave functions, in which the main design parameters correspond to the amplitudes of sinewave functions. A systematic procedure is followed to select synthesis parameters, which depend only on the number of cascaded comb filters. In particular, they are independent of the decimation factor. Comparisons with comb compensators from literature illustrate the benefits of the proposed design.

Efficient wide‐band droop compensation for CIC filters: ad hoc and reconfigurable FIR architectures

“…The advantages of the proposed architectures are evident. For N = 1, the proposed solution achieves nine times better compensation characteristics with just 1.5 times the complexity of the second-order compensator from [4]. For other Ns, the passband deviations are better, in general (except for N = 6, where the deviation of the proposed system is slightly worst), and the proposed solutions are faster and more power-and area-efficient.…”

“…when a higher attenuation is specified for aliasing rejection. This droop is particularly undesirable in the wide-band scenario, and thus the improvement of the passband magnitude characteristic of CIC filters for this case has been recently investigated in [3,4], where lowcomplexity multiplier-less designs have been developed (the previous research on the subject was addressed in [5][6][7], among others, where multipliers are avoided due to their undesirably high computational and implementation costs [8]). We pointed out in our preliminary work [3] that with a fourth-order compensator it is possible to achieve nearly four times better droop compensation with less than twice the computational complexity of the recent second-order compensators available in the literature.…”

“…However, that work presented nonreconfigurable finite impulse response (FIR) architectures derived from a heuristic design method to find the multiplier-less coefficients. A different heuristic was recently employed in [4], where sixth-order compensators were designed for the typical cases of N: namely, between 1 and 6 (for N = 1, the compensator becomes a second-order filter). Even though a reconfigurable architecture for those Ns was mentioned, only ad hoc compensators were compared and reported without any post-place-and-route (PAR) information.…”

“…These parameters are configured as shown in Table 2. [4], we have made adjustable for N the multiplier-less coefficients (called B 1 and B 2 ) of the ad hoc compensators in [4], just as we did with coefficients g(0) and g(1) of our proposed solution. N was set between 1 and 6 (as documented in [4]).…”

“…[4], we have made adjustable for N the multiplier-less coefficients (called B 1 and B 2 ) of the ad hoc compensators in [4], just as we did with coefficients g(0) and g(1) of our proposed solution. N was set between 1 and 6 (as documented in [4]). The value change dump information generated by ModelSim was used in the power play power analyser to estimate power dissipation with high level of confidence, and TimeQuest Timing Analyser was employed for the estimation of performance, using the slow 85C timing model (the worst-case scenario).…”